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Title:
Detection and diagnosis of smoking related cancers
United States Patent: 8,093,001
Issued: January 10, 2012
Inventors: Katz; Ruth
(Houston, TX), Jiang; Feng (Houston, TX)
Assignee:
Board of Regents, The University of Texas System (Austin, TX)
Appl. No.: 12/761,134
Filed: April 15, 2010
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Training Courses --Pharm/Biotech/etc.
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Abstract
Gene probes for specific regions of
chromosome 3 (3p21.3) and chromosome 10 (10q22) have been found to be
tools for the diagnosis and prognosis of smoking related cancers such as
non-small cell lung cancer (NSCLC). For example, these probes can be used
with fluorescence in situ hybridization (FISH), and used to stratify
smokers into high and low risk groups, as well as determine a patients
susceptibility to the development of smoking related cancers.
Description of the
Invention
SUMMARY OF THE INVENTION
The present invention provides probes located on chromosomes 3p21.3 and
10q22 useful in the diagnosis and prognosis of cancers related to smoking.
In one embodiment, a method for identifying a subject at high risk for the
development, recurrence, or metastasis of cancer comprising the steps of
(a) obtaining a test sample from a subject; (b) providing a nucleic acid
probe targeting RPL14, CD39L3, PMGM, or GC20; (c) contacting the probe
with the test sample; and (d) analyzing DNA from the sample whereby
aberrations in the hybridization of said probe to said DNA was compared to
wild type DNA, indicating the risk for the development, recurrence, or
metastasis of cancers.
More specifically the method identifies the risk for the development of
cancers. The cancer may be lung, upper airway primary or secondary, head
or neck, bladder, kidneys, pancreas, mouth, throat, pharynx, larynx,
esophagus, brain, liver, spleen, kidney, lymph node, small intestine,
pancreas, blood cells, colon, stomach, breast, endometrium, prostate,
testicle, ovary, skin, bone marrow and blood cancer. In preferred
embodiments, the cancer is lung cancer. The test sample can include, but
is not limited to, a surgical or biopsy specimen, paraffin embedded
tissue, frozen tissue, surgical fine needle aspirations, bronchial
brushes, bronchial washes, bronchial lavages, buccal smears, sputa,
peripheral blood lymphocytes, esophageal brush, a fine needle aspiration,
urinary specimens such as bladder washings and voided urine, and
esophageal washes.
In one embodiment, it is provided that the subject can come from a group
comprising smokers, former smokers, or non-smokers. In a similar
embodiment, the test sample comes from said subject who has not previously
been diagnosed with cancer.
It is a further embodiment of this invention that additional testing,
agents or treatments may be performed after the risk for the development
of said cancers has been analyzed. This includes, but is not limited to, a
spiral CT-scan, cancer therapies and pharmaceutical treatments which can
include radiotherapeutic agents, surgical treatment for removal of the
cancerous growth, chemotherapeutic agents, antibiotics, alkylating agents
and antioxidants, biological modifying respidase drugs and other agents.
These agents and treatments can be used alone or in combination with other
agents.
In certain embodiments, it is contemplated that FISH is used to measure
the aberrations in the particular loci. A unique 3p21.3 probe can be from
1000 to 2000 base pairs or larger and used for detection in a region of
about 180,000 base pairs. The probe can be labeled with a fluorophore, or
more specifically digoxigenin. A specific 10q22 probe can be used in
conjunction with the 3p21 probe. In certain embodiments, a control probe
is used which can be labeled with a fluorophore, or more specifically
spectrum orange. The control probe is a chromosome 3 stable marker or more
specifically Centromere 3 (CEP 3).
In another embodiment, there is provided a method for identifying a
subject at high risk for the development, recurrence, or metastasis of
cancer comprising: (a) obtaining a lung test sample from a subject; (b)
providing a specific10q22 DNA probe; (c) contacting said probe with said
test sample; and (d) analyzing DNA from said test sample, whereby
aberrations in the hybridization of said probe to said DNA is compared to
wild type DNA, indicating the risk for the development, recurrence or
metastasis of said cancers. More specifically the method identifies the
risk of the recurrence or metastasis of cancers. In a further embodiment,
the probe size is from 1000 to 2000 base pairs or larger, for detection in
a region of about 200,000 base pairs. In an additional embodiment, a
specific 3p21 probe can be used with the 10q22 DNA probe. The control
probe is a chromosome 10 stable marker, or more specifically Centromere10
(CEP10).
In another embodiment, there is provided a method for predicting the
progression or metastasis of non-small cell carcinoma and other carcinoma
in a subject comprising: (a) obtaining a test sample from a subject; (b)
providing a RPL14, CD39L3, PMGM, or GC20 gene probe; (c) contacting said
probe with said test sample; and (d) analyzing DNA from said test sample.
In yet another embodiment, there is provided a method for predicting the
progression or metastasis of non-small cell carcinoma in a subject
comprising: (a) obtaining a lung test sample from a subject; (b) providing
a specific10q22 DNA probe; (c) contacting said probe with said test
sample; and (d) analyzing DNA from said test sample.
In a further embodiment, there is provided a method for the staging lung
of cancer in a subject comprising determining the deletion distribution of
the 3p21.3 region.
In one embodiment, there is provided a method of determining likelihood of
relapse or a new primary for a cancer subject comprising determining
genetic aberrations at chromosomal loci 3p21.3 or 10q22 in DNA of
bronchial tissue adjacent to tumor tissue from said subject, wherein
abnormalities in DNA of said adjacent tissue correlate with relapse of
said cancer. The cancer can comprise lung cancer or more specifically
non-small cell carcinoma, adenocarcinoma, or squamous cell carcinoma. A
specific gene probe may comprise RPL 14, CD39L3, PMGM, or GC20, or a 10q22
DNA probe. The 10q22 probe lies adjacent to the PTEN gene which is
frequently involved non-small cell cancer. Both the 3p and the 10q probe
can be used simultaneously. The test sample can be chosen from the same or
contralateral lung, and can consist of tumorous or nontumorous bronchial
cells.
In yet another embodiment, there is provided a method of identifying an
individual to be segregated from a high risk environment comprising: (a)
obtaining a test sample from a subject; (b) providing a gene probe
containing RPL14, CD39L3, PMGM, and GC20 genes and PTEN or a 10q22 DNA
probe, (c) contacting said probe with said test sample; and (d) analyzing
DNA from said test sample, whereby said analysis is used to identify an
individual who is highly susceptible to the development of lung cancer and
who should not be exposed to a high risk environment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
I. The Present Invention
As stated above, deletions in the 3p21.3 and 10q22 regions of human
chromosomes 3 and the 10 have been shown to be associated with cancers.
The present invention has shown these regions also to be predictive of the
development of neoplasia and progression of neoplastic events. In
particular embodiments, the inventors have developed novel DNA FISH probes
and tested them on patients at M. D. Anderson Cancer Center (MDACC) in
early stage non-small cell lung neoplasms using archival tissue from stage
I non-small cell cancers.
The probes are used in the early detection of cancer and in
chemopreventive studies as an intermediate biomarker. Until now there have
been no reports about the application of these DNA probes to paraffin
embedded clinical tumor specimens using fluorescence in situ hybridization
(FISH) and microdissection. The FISH technique allows the measurement of
an average level of deletion of a gene in a tumor, as well as the actual
number and distribution of the gene in individual, morphological cells.
The inventors propose that deletion distribution of the RPL14, CD39L3,
PMGM or GC20 genes and 10q22 locus are useful as a diagnostic tool in
determining the stage of lung cancer patients.
A. Smoking Related Cancers
The current invention is useful for the prognosis and diagnosis of lung
cancers, which can be defined by a number of histologic classifications
including: squamous cell carcinomas such as squamous carcinoma; small cell
carcinomas such as oat cell carcinoma, intermediate cell type carcinoma,
combined oat and cell carcinoma; adenocarcinomas such as acinar
adenocarcinoma, papillary adenocarcinoma, bronchioloalveolar carcinoma,
and solid carcinoma with mucus formation; large cell carcinoma such as
giant cell carcinoma and clear cell carcinoma; adenosquamous carcinoma;
carcinoid; and bronchial gland carcinomas such as adenoid cystic, and
mucoepidermoid carcinoma. Diagnosis and prognosis of other smoking related
cancers is possible with these probes. Squamous cell carcinoma of the head
and neck has the same risk factors as lung cancer is hypothesized to have
similar etiology (Shriver, 1998). Similarly, smoking is an etiological
factor for cancer of the bladder, head, neck, kidneys, pancreas, and
cancer of the upper airways including cancer of the mouth, throat,
pharynx, larynx, or esophagus.
B. Tumorgenesis
The deletions of various genes in tumor tissue has been well studied in
the art. However, there remains a need for probes that are significant for
detecting early molecular events in the development of cancers, as well as
molecular events that make patients susceptible to the development of
cancer. Probes used for the staging of cancer are also of interest. The
proposed sequence leading to tumorigenesis includes genetic instability at
the cellular or submicroscopic level as demonstrated by loss or gain of
chromosomes, leading to a hyperproliferative state due to theoretical
acquisition of factors that confer a selective proliferative advantage.
Further, at the genetic level, loss of function of cell cycle inhibitors
and tumor suppressor genes (TSG), or amplification of oncogenes that drive
cell proliferation, are implicated.
Following hyperplasia, a sequence of progressive degrees of dysplasia,
carcinoma-in-situ and ultimately tumor invasion is recognized on
histology. These histologic changes are both preceded and paralleled by a
progressive accumulation of genetic damage. At the chromosomal level
genetic instability is manifested by a loss or gain of chromosomes, as
well as structural chromosomal changes such as translocation and
inversions of chromosomes with evolution of marker chromosomes. In
addition cells may undergo polyploidization. Single or multiple clones of
neoplastic cells may evolve characterized in many cases by aneuploid cell
populations. These can be quantitated by measuring the DNA content or
ploidy relative to normal cells of the patient by techniques such as flow
cytometry or image analysis.
C. Prognostic Factors and Staging
At present, the most important prognostic factor regarding the survival of
patients with lung cancer of non-small cell type is the stage of disease
at diagnosis. Small cell cancer usually presents with wide spread
dissemination hence the staging system is less applicable. The staging
system was devised based on the anatomic extent of cancer and is now know
as the TNM system based on anatomical size and spread within the lung and
adjacent structures, regional lymph nodes and distant metastases. The only
hope presently for a curative procedure lies n the operability of the
tumor which can only be resected when the disease is at a low sage, that
is confined to the lung.
D. Grading of Tumors
The histological type and grade of lung cancer do have some prognostic
impact within the stage of disease with the best prognosis being reported
for stage I adenocarcinoma, with 5 year survival at 50% and 1-year
survival at 65% and 59% for the bronchiolar-alveolar and papillary
subtypes (Naruke et al., 1988; Travis et al., 1995; Carriaga et al.,
1995). For squamous cell carcinoma and large cell carcinoma the 5 year
survival is around 35%. Small cell cancer has the worst prognosis with a 5
year survival rate of only 12% for patients with localized disease (Carcy
et al., 1980; Hirsh, 1983; Vallmer et al., 1985). For patients with
distant metastases survival at 5 years is only 1-2% regardless of
histological subtype (Naruke et al., 1988). In addition to histological
subtype, it has been shown that histological grading of carcinomas within
subtype is of prognostic value with well differentiated tumors having a
longer overall survival than poorly differentiated neoplasms. Well
differentiated localized adencarcinoma has a 69% overall survival compared
to a survival rate of only 34% of patients with poorly differentiated
adenocarcinoma (Hirsh, 1983). The 5 year survival rates of patients with
localized squamous carcinoma have varied from 37% for well differentiated
neoplasms to 25% for poorly differentiated squamous carcinomas (Ihde,
1991).
The histologic criteria for subtyping lung tumors is as follows: squamous
cell carcinoma consists of a tumor with keratin formation, keratin pearl
formation, and/or intercellular bridges. Adenocarcinomas consist of a
tumor with definitive gland formation or mucin production in a solid
tumor. Small cell carcinoma consists of a tumor composed of small cells
with oval or fusiform nuclei, stippled chromatin, and indistinct nuclei.
Large cell undifferentiated carcinoma consists of a tumor composed of
large cells with vesicular nuclei and prominent nucleoli with no evidence
of squamous or glandular differentiation. Poorly differentiated carcinoma
includes tumors containing areas of both squamous and glandular
differentiation.
E. Development of Carcinomas
The evolution of carcinoma of the lung is most likely representative of a
field cancerization effect as a result of the entire aero-digestive system
being subjected to a prolonged period of carcinogenic insults such as
benzylpyrenes, asbestosis, air pollution and chemicals other carcinogenic
substances in cigarette smoke or other environmental carcinogens. This
concept was first proposed by Slaughter et al. (1953). Evidence for
existence of a field effect is the common occurrence of multiple
synchronous for metachronous second primary tumors (SPTs) that may develop
throughout the aero-digestive tract in the oropharynx, upper esophagus or
ipsilateral or contralateral lung.
Accompanying these molecular defects is the frequent manifestation of
histologically abnormal epithelial changes including hyperplasia,
metaplasia, dysplasia, and carcinoma-in-situ. It has been demonstrated in
smokers that both the adjacent normal bronchial epithelium as well as the
preneoplastic histological lesions may contain clones of genetically
altered cells. (Wistuba et al., 2000).
Liciardello et al. (1989) found a 10-40% incidence of metachronous tumors
and a 9-14% incidence of synchronous SPTs in the upper and lower
aero-digestive tract, mostly in patients with the earliest primary tumors
SPTs may impose a higher risk than relapse from the original primary tumor
and may prove to be the major threat to long term survival following
successful therapy for early stage primary head, neck or lung tumors.
Hence it is vitally important to follow these patients carefully for
evidence of new SPTs in at risk sites for new malignancies specifically in
the aero-digestive system.
In addition to chromosomal changes at the microscopic level, multiple
blind bronchial biopsies may demonstrate various degrees of
intraepithelial neoplasia at loci adjacent to the areas of lung cancer.
Other investigators have shown that there are epithelial changes ranging
from loss of cilia and basal cell hyperplasia to CIS in most light and
heavy smokers and all lungs that have been surgically resected for cancer.
(Auerbach et al., 1961). Voravud et al. (1993) demonstrated by in-situ
hybridization (ISH) studies using chromosome-specific probes for
chromosomes 7 and 17 that 30-40% of histologically normal epithelium
adjacent to tumor showed polysomies for these chromosomes. In addition
there was a progressive increase in frequency of polysomies in the tissue
closest to the carcinoma as compared to normal control oral epithelium
from patients without evidence of carcinoma. The findings of genotypic
abnormalities that increased closer to the area of the tumor support the
concept of field cancerization. Interestingly there was no increase in DNA
content as measured in the normal appearing mucosa in a Feulgen stained
section adjacent to the one where the chromosomes were measured,
reflecting perhaps that insufficient DNA had been gained in order to alter
the DNA index. Interestingly a very similar increase in DNA content was
noted both in dysplastic areas close to the cancer and in the cancerous
areas suggesting that complex karyotypic abnormalities that are clonal
have already been established in dysplastic epithelium adjacent to lung
cancer. Others have also shown an increase in number of cells showing p53
mutations in dysplastic lesions closest to areas of cancer, which are
invariably also p53 mutated. Other chromosomal abnormalities that have
recently been demonstrated in tumors and dysplastic epithelium of smokers
includes deletions of 3p, 17p, 9 p and 5q (Feder et al., 1998; Yanagisawa
et al., 1996; Thiberville et al., 1995).
F. Chromosome Deletions in Lung Cancer
Small cell lung cancer (SCLC) and non-small cell lung cancer commonly
display cytogenetically visible deletions on the short arm of chromosome 3
(Hirano et al., 1994; Valdivieso et al., 1994; Cheon et al., 1993; Pence
et al., 1993). This 3p deletion occurs more frequently in the lung tumor
tissues of patients who smoke than it does in those of nonsmoking patient.
(Rice et al., 1993) Since approximately 85% lung cancer patients were
heavy cigarette smokers (Mrkve et al., 1993), 3p might contain specific
DNA loci related to the exposure of tobacco carcinogens. It also has been
reported that 3p deletion occurs in the early stages of lung
carcinogenesis, such as bronchial dysplasia (Pantel et al., 1993). In
addition to cytogenetic visible deletions, loss of heterozygosity (LOH)
studies have defined 3-21.3 as one of the distinct regions that undergo
loss either singly or in combination (Fontanini et al., 1992; Liewald et
al., 1992). Several other groups have found large homozygous deletions at
3p21.3 in lung cancer (Macchiarini et al., 1992; Miyamoto et al., 1991;
Ichinose et al., 1991; Yamaoka et al., 1990). Transfer of DNA fragments
from 3-21.3-3p21.2 into lung tumor cell lines could suppress the
tumorigenesis. (Sahin et al., 1990; Volm et al., 1989). These finding
strongly suggest the presence of at least one tumor suppressor gene in
this specific chromosome region whose loss will initiate lung
carcinogenesis.
Cytogenetic observation of lung cancer has shown an unusual consistency in
the deletion rate of chromosome 3p. In fact, small cell lung cancer (SCLC)
demonstrates a 100% deletion rate within certain regions of chromosome 3p.
Non small cell lung cancer (NSCLC) demonstrates a 70% deletion rate (Mitsudomi
et al., 1996; Shiseki et al., 1996). Loss of heterozygosity and
comparative genomic hybridization analysis have shown deletions between
3p14.2 and 3p21.3 to be the most common finding for lung carcinoma and is
postulated to be the most crucial change in lung tumorigenesis (Wu et al.,
1998). It has been hypothesized that band 3p21.3 is the location for lung
cancer tumor suppressor genes. The hypothesis is supported by chromosome 3
transfer studies, which reduced tumorigenicity in lung adenocarcinoma.
Allelotype studies on non-small cell lung carcinoma indicated loss of
genetic material on chromosome 10q in 27% of cases. Studies of chromosome
10 allelic loss have shown that there is a very high incidence of LOH in
small cell lung cancer, up to 91%. (Alberola et al., 1995; Ayabe et al.,
1994). A statistically significant LOH of alleles on 10q was noted in
metastatic squamous cell carcinoma (SCC) in 56% of cases compared to non-metastatic
SCC with LOH seen in only 14% of cases. (Ayabe et al., 1994). No LOH was
seen in other subtypes on NSCLC. Peterson (1995) used paired samples of
tumor and normal tissue to assess LOB. By micro-satellite polymorphism
analysis, a high incidence of loss was found between D10s677 and D10S1223.
This region spans the long arm of chromosome 10 at bands q21-q24 and
overlaps the region deleted in the a study of advanced stage high grade
bladder cancers which demonstrated a high frequency of allele loss within
a 2.5cM region at 10q22.3-10q23.1 (Kim et al., 1996).
II. The 3p21.3 Gene Probes
A. Structural Features
Recently, the human ribosomal L14 (RPL14) gene (GenBank Accession
NM_003973, SEQ ID NO: 1), and the genes CD39L3 (GenBank Accession AAC39884
and AF039917; SEQ ID NO: 3), PMGM (GenBank Accession P15259 and J05073;
SEQ ID NO: 5), and GC20 (GenBank Accession NM.sub.--005875; SEQ ID NO: 7)
were isolated from a BAC (GenBank Accession AC019204, herein incorporated
by reference) and located in the 3p21.3 band within the smallest region of
deletion overlap of various lung tumors. The RPL14 gene sequence contains
a highly polymorphic trinucleotide (CTG) repeat array, which encodes a
variable length polyalanine tract. Polyalanine tracts are found in gene
products of developmental significance that bind DNA or regulate
transcription. For example, Drosophila proteins Engraled, Kruppel and
Even-Skipped all contain polyalanine tracts that act as transcriptional
repressors. Genotype analysis of RPL14 shows that this locus is 68%
heterozygous in the normal population, compared with 25% in NSCLC cell
lines. Cell cultures derived from normal bronchial epithelium show a 65%
level of heterozygosity, reflecting that of the normal population.
B. Functional Aspects
Genes with a regulatory function such as the RPL14 gene (SEQ ID NO: 1),
along with the genes CD39L3, PMGM, and GC20 (SEQ ID NOS: 3, 5 and 7) and
analogs thereof, are good candidates for diagnosis of tumorigenic events.
It has been postulated that functional changes of the RPL14 protein (SEQ
ID NO: 2) can occur via a DNA deletion mechanism of the trinucleotide
repeat encoding for the protein. This deletion mechanism makes the RPL14
gene and attractive sequence that may be used as a marker for the study of
lung cancer risk (Shriver et al., 1998). In addition, the RPL14 gene shows
significant differences in allele frequency distribution in ethnically
defined populations, making this sequence a useful marker for the study of
ethnicity adjusting lung cancer (Shriver et al., 1998). Therefore, this
gene is useful in the early detection of lung cancer, and in
chemopreventive studies as an intermediate biomarker.
III. The 10q22 Gene Probes
A. Structural Features
The 10q22 BAC (46b12) is 200 Kb and is adjacent and centromeric to PTEN/MMAC1
(GenBank Accession AF067844), which is at 10q22-23 and can be purchased
through Research Genetics (Huntsville, Ala.). Alterations to 10q22-25 has
been associated with multiple tumors, including lung, prostate, renal, and
endomentrial carcinomas, melanoma, and meningiomas, suggesting the
possible suppressive locus affecting several cancers in this region. The
PTEN/MMAC1 gene, encoding a dual-specificity phosphatase, is located in
this region, and has been isolated as a tumor suppressor gene that is
altered in several types of human tumors including brain, bladder, breast
and prostate cancers. PTEN/MMAC1 mutations have been found in some cancer
cell lines, xenografts, and hormone refractory cancer tissue specimens.
Because the inventor's 10q22 BAC DNA sequence is adjacent to this region,
the DNA sequences in the BAC 10q22 may be involved in the genesis and/or
progression of human lung cancer.
B. Functional Aspects
Functional evidence for the presence of tumor suppressor genes on 10q has
been provided by microcell-mediated chromosomal transfer. The resulting
hybrid clones displayed a suppressed tumorigenic phenotype with the
inability to proliferate in nude mice and soft agarose. Sequence analysis
of the PTEN/MMAC1 gene in lung cancer revealed a G to C substitution
located 8 bp upstream of the coding region of exon1 and which seems to be
a polymorphism, in 4 of the 30 cases of lung cancer tested. Somatic
mutations of the TPEN/MMAC1 gene were not identified in any of the tumors
at the primary and metastatic sites of lung cancer, indicating that point
mutations in the PTEN/MMAC1 gene are probably not an important factor in
tumorigenesis and the progression of a major subset of lung cancers. Other
more important tumor suppressor genes must lie close to the PTEN/MMAC1
gene, in the vicinity of the inventors' 10q22 BAC locus. Therefor, the
10q22 probe is useful in the further development of clinical biomarkers
for the early detection of neoplastic events, for risk assessment and
monitoring the efficacy of chemoprevention therapy in high risk former or
current smokers.
IV. Nucleic Acids
The inventors' have identified the probes for the human chromosome region
3p21.3 and human chromosome region 10q22. In addition, it should be clear
that the present invention is not limited to the specific nucleic acids
disclosed herein.
A. Probes and Primers
Naturally, the present invention encompasses DNA segments that are
complementary, or essentially complementary, to target sequences. Nucleic
acid sequences that are "complementary" are those that are capable of
base-pairing according to the standard Watson-Crick complementary rules.
As used herein, the term "complementary sequences" means nucleic acid
sequences that are substantially complementary, as may be assessed by the
same nucleotide comparison set forth above, or as defined as being capable
of hybridizing to a target nucleic acid segment under relatively stringent
conditions such as those described herein. These probes may span hundreds
or thousands of base pairs.
Alternatively, the hybridizing segments may be shorter oligonucleotides.
Sequences of 17 bases long should occur only once in the human genome and,
therefore, suffice to specify a unique target sequence. Although shorter
oligomers are easier to make and increase in vivo accessibility, numerous
other factors are involved in determining the specificity of
hybridization. Both binding affinity and sequence specificity of an
oligonucleotide to its complementary target increases with increasing
length. It is contemplated that exemplary oligonucleotides of about 8, 9,
10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, 50, 55,
60, 65, 70, 75, 80, 85, 90, 95, 100, 250, 500, 700, 722, 900, 992, 1000,
1500, 2000, 2500, 2800, 3000, 3500, 3800, 4000, 5000 or more base pairs
will be used, although others are contemplated. As mentioned above, longer
polynucleotides encoding 7000, 10000. 12000 bases and longer are
contemplated as well. Such oligonucleotides will find use, for example, as
probes in FISH, Southern and Northern blots and as primers in
amplification reactions.
It will be understood that this invention is not limited to the particular
probes disclosed herein and particularly is intended to encompass at least
nucleic acid sequences that are hybridizable to the disclosed sequences or
are functional sequence analogs of these sequences. For example, a partial
sequence may be used to identify a structurally-related gene or the full
length genomic or cDNA clone from which it is derived. Those of skill in
the art are well aware of the methods for generating cDNA and genomic
libraries which can be used as a target for the above-described probes (Sambrook
et al., 1989).
For applications in which the nucleic acid segments of the present
invention are incorporated into vectors, such as plasmids, cosmids or
viruses, these segments may be combined with other DNA sequences, such as
promoters, polyadenylation signals, restriction enzyme sites, multiple
cloning sites, other coding segments, and the like, such that their
overall length may vary considerably. It is contemplated that a nucleic
acid fragment of almost any length may be employed, with the total length
preferably being limited by the ease of preparation and use in the
intended recombinant DNA protocol.
DNA segments encoding a specific gene may be introduced into recombinant
host cells and employed for expressing a specific structural or regulatory
protein. Alternatively, through the application of genetic engineering
techniques, subportions or derivatives of selected genes may be employed.
Upstream regions containing regulatory regions such as promoter regions
may be isolated and subsequently employed for expression of the selected
gene.
B. Labeling of Probes
In certain embodiments, it will be advantageous to employ nucleic acid
sequences of the present invention in combination with an appropriate
means, such as a label, for determining hybridization. A wide variety of
appropriate indicator means are known in the art, including fluorescent,
radioactive, chemiluminescent, electroluminescent, enzymatic tag or other
ligands, such as avidin/biotin, antibodies, affinity labels, etc., which
are capable of being detected. In preferred embodiments, one may desire to
employ a fluorescent label such as digoxigenin, spectrum orange,
fluorosein, eosin, an acridine dye, a rhodamine, Alexa 350, Alexa 430,
AMCA, BODIPY 630/650, BODIPY 650/665, BODIPY-FL, BODIPY-R6G, BODIPY-TMR,
BODIPY-TRX, cascade blue, Cy2, Cy3, Cy5,6-FAM, HEX, 6-JOE, Oregon green
488, Oregon green 500, Oregon green 514, pacific blue, REG, ROX, TAMRA,
TET, or Texas red.
In the case of enzyme tags such as urease alkaline phosphatase or
peroxidase, colorimetric indicator substrates are known which can be
employed to provide a detection means visible to the human eye or
spectrophotometrically, to identify specific hybridization with
complementary nucleic acid-containing samples. Examples of affinity labels
include but are not limited to the following: an antibody, an antibody
fragment, a receptor protein, a hormone, biotin, DNP, or any
polypeptide/protein molecule that binds to an affinity label and may be
used for separation of the amplified gene.
The indicator means may be attached directly to the probe, or it may be
attached through antigen bonding. In preferred embodiments, digoxigenin is
attached to the probe before denaturization and a fluorophore labeled
anti-digoxigenin FAB fragment is added after hybridization.
C. Hybridization Conditions
Suitable hybridization conditions will be well known to those of skill in
the art. Conditions may be rendered less stringent by increasing salt
concentration and decreasing temperature. For example, a medium stringency
condition could be provided by about 0.1 to 0.25 M NaCl at temperatures of
about 37.degree. C. to about 55.degree. C., while a low stringency
condition could be provided by about 0.15 M to about 0.9 M salt, at
temperatures ranging from about 20.degree. C. to about 55.degree. C. Thus,
hybridization conditions can be readily manipulated, and thus will
generally be a method of choice depending on the desired results.
In other embodiments, hybridization may be achieved under conditions of,
for example, 50 mM Tris-HCl (pH 8.3), 75 mM KCl, 3 mM MgCl.sub.2, 10 mM
dithiothreitol, at temperatures between approximately 20.degree. C. to
about 37.degree. C. Other hybridization conditions utilized could include
approximately 10 mM Tris-HCl (pH 8.3), 50 mM KCl, 1.5 .mu.M MgCl.sub.2, at
temperatures ranging from approximately 40.degree. C. to about 72.degree.
C. Formamide and SDS also may be used to alter the hybridization
conditions.
V. Biomarkers
Various biomarkers of prognostic significance can be used in conjunction
with the 3p21.3 or the 10q22 nucleic acid probes. These biomarkers could
aid in predicting the survival in low stage cancers and the progression
from preneoplastic lesions to invasive lung cancer. These markers can
include proliferation activity as measured by Ki-67 (MIB1), angiogenesis
as quantitated by expression of VEGF and microvessels using CD34, oncogene
expression as measured by erb B2, and loss of tumor suppresser genes as
measured by p53 expression.
Multiple biomarker candidates have been implicated in the evolution of
neoplastic lung lesions. Bio-markers that have been studies include
general genomic markers including chromosomal alterations, specific
genomic markers such as alterations in proto-oncogenes such as K-Ras,
Erb.beta.1/EGFR, Cyclin D; proliferation markers such as Ki67 or PCNA,
squamous differentiation markers, and nuclear retinoid receptors (Papadimitrakopoulou
et al., 1996) The latter are particularly interesting as they may be
modulated by specific chemopreventive drugs such as 13-cis-retinoic acid
or 4HPR and culminate in apoptosis of the defective cells with restoration
of a normally differentiated mucosa (Zou et al., 1998).
A. Tumor Angiogenesis by Microvessel Counts
Tumor angiogenesis can be quantitated by microvessel density and is a
viable prognostic factor in stage 1 NSCLC. Tumor microvessel density
appears to be a good predictor of survival in stage 1 NSCLC.
B. Vascular Endothelial Growth Factor (VEGF)
VEGF (3, 6-8 ch 4) an endothelial cell specific mitogen is an important
regulator of tumor angiogenesis who's expression correlates well with
lymph node metastases and is a good indirect indicator of tumor
agniogenesis. VEGF in turn is upregulated by P53 protein accumulation in
NSCLC.
C. p53
The role of p53 mutations in predicting progression and survival of
patients with NSCLC is widely debated. Although few studies imply a
negligible role, the majority of the studies provide compelling evidence
regarding the role of p53 as one of the prognostic factors in NSCLC. The
important role of p53 in the biology of NSCLC has been the basis for
adenovirus mediated p53 gene transfer in patients with advanced NSCLC (Carcy
et al., 1980). In addition p53 has also been shown to be an independent
predictor of chemotherapy response in NSCLC. In a recent study (Valimer et
al., 1985), the importance of p53 accumulation in preinvasive bronchial
lesions from patients with lung cancer and those who did not progress to
cancer were studied. It was demonstrated that p53 accumulation in
preneoplastic lesions had a higher rate of progression to invasion than
did p53 negative lesions.
D. c-erb-B2
Similar to p53, c-erg-B2 (Her2/neu) expression has also been shown to be a
good marker of metastatic propensity and an indicator of survival in these
tumors.
E. Ki-67 Proliferation Marker
In addition to the above markers, tumor proliferation index as measured by
the extent of labeling of tumor cells for Ki-67, a nuclear antigen
expressed throughout cell cycle correlates significantly with clinical
outcome in Stage 1 NSCLC (Feinstein et al., 1970). The higher the tumor
proliferation index the poorer is the disease free survival labeling
indices provides significant complementary, if not independent prognostic
information in Stage 1 NSCLC, and helps in the identification of a subset
of patients with Stage 1 NSCLC who may need more aggressive therapy.
VI. Prognosis and Diagnosis of Cancers Using 3p21.3 and 10q22 Gene Probes
Alterations in the 3p21.3 and 10q22 loci are known to be associated with a
number of cancers. More specifically, point mutations, deletions,
insertions or regulatory perturbations relating to the 3p21.3 and 10q22
loci may cause cancer or promote cancer development, cause or promoter
tumor progression at a primary site, and/or cause or promote metastasis.
Other phenomena at the 3p21.3 and 10q22 loci include angiogenesis and
tissue invasion. Thus, the present inventors have demonstrated that
deletions at 3p21.3 and 10q22 can be used not only as a diagnostic or
prognostic indicator of cancer, but to predict specific events in cancer
development, progression and therapy.
A variety of different assays are contemplated in this regard, including
but not limited to, fluorescent in situ hybridization (FISH), direct DNA
sequencing, PFGE analysis, Southern or Northern blotting, single-stranded
conformation analysis (SSCA), RNase protection assay, allele-specific
oligonucleotide (ASO), dot blot analysis, denaturing gradient gel
electrophoresis, RFLP and PCR-SSCP.
Various types of defects are to be identified. Thus, "alterations" should
be read as including deletions, insertions, point mutations and
duplications. Point mutations result in stop codons, frameshift mutations
or amino acid substitutions. Somatic mutations are those occurring in non-germline
tissues. Germ-line tissue can occur in any tissue and are inherited.
A. Samples
One embodiment of the instant invention comprises a method for detecting
variation in the hybridization of the probes to DNA. This may comprise
determining specific alterations in the expressed product, or may simply
involve detecting gross structural abnormalities. Such cancer may involve
cancers of the lung, upper airway primary or secondary cancer, bladder,
urithial, head and neck, esophagus, kidney, pancreas, mouth, throat,
pharynx, larynx, brain, liver, spleen, small intestine, blood cells, lymph
node, colon, breast, endometrium, stomach, prostate, testicle, ovary,
skin, bone marrow, blood or other tissue.
In particular, the present invention relates to the diagnosis and
prognosis of smoking related cancers. More particularly, the present
invention relates to the diagnosis and prognosis of lung cancer which
includes, but is not limited to: squamous cell carcinomas such as squamous
carcinoma; small cell carcinomas such as oat cell carcinoma, intermediate
cell type carcinoma, combined oat and cell carcinoma; adenocarcinomas such
as acinar adenocarcinoma, papillary adenocarcinoma, bronchioloalveolar
carcinoma, and solid carcinoma with mucus formation; large cell carcinoma
such as giant cell carcinoma and clear cell carcinoma; adenosquamous
carcinoma; carcinoid; and bronchial gland carcinomas such as adenoid
cystic, and mucoepidermoid carcinoma.
The biological sample can be any tissue or fluid that contains nucleic
acids. Various embodiments include paraffin imbedded tissue, frozen
tissue, surgical fine needle aspirations, cells of the skin, muscle, lung,
head and neck, esophagus, kidney, pancreas, mouth, throat, pharynx,
larynx, esophagus, facia, brain, prostate, breast, endometrium, small
intestine, blood cells, liver, testes, ovaries, colon, skin, stomach,
spleen, lymph node, bone marrow or kidney. Other embodiments include fluid
samples such as bronchial brushes, bronchial washes, bronchial lavages,
peripheral blood lymphocytes, lymph fluid, ascites, serous fluid, pleural
effusion, sputum, cerebrospinal fluid, lacrimal fluid, esophageal washes,
stool or urinary specimens such as bladder washing and urine.
Bronchial washes sample more area of bronchial epithelium but are also
frequently cytologically normal. A more complete sampling of the
respiratory passages may occur with a bronchiolar alveolar lavage in which
both left and right proximal and distal small bronchi and bronchioles are
washed out.
Nucleic acids are isolated from cells contained in the biological sample,
according to standard methodologies (Sambrook et al., 1989). The nucleic
acid may be genomic DNA or fractionated or whole cell RNA. Where RNA is
used, it may be desired to convert the RNA to a complementary DNA.
Depending on the format, the specific nucleic acid of interest is
identified in the sample directly using amplification or with a second,
known nucleic acid following amplification. Next, the identified product
is detected. The detection may involve indirect identification of the
product via fluorescent label, chemiluminescence, radioactive scintigraphy
of radiolabel or even via a system using electrical or thermal impulse
signals (Affymax Technology; Bellus, 1994). Alternatively, the detection
may be performed by visual means (e.g., ethidium bromide staining of a
gel).
Following detection, one may compare the results seen in a given sample
with a statistically significant reference group of samples from normal
patients and patients that have or lack alterations in chromosome loci
3p21.3 or 10q22. In this way, it is possible to correlate the amount or
kind of alterations detected with various clinical states.
B. Fluorescence In Situ Hybridization
Fluorescence in situ hybridization (FISH) can be used for molecular
studies. FISH is used to detect highly specific DNA probes which have been
hybridized to chromosomes using fluorescence microscopy. The DNA probe is
labeled with fluorescent or non fluorescent molecules which are then
detected by fluorescent antibodies. The probes bind to a specific region
or regions on the target chromosome. The chromosomes are then stained
using a contrasting color, and the cells are viewed using a fluorescence
microscope.
Each FISH probe is specific to one region of a chromosome, and is labeled
with fluorescent molecules throughout it's length. Each microscope slide
contains many metaphases. Each metaphase consists of the complete set of
chromosomes, one small segment of which each probe will seek out and bind
itself to. The metaphase spread is useful to visualize specific
chromosomes and the exact region to which the probe binds. The first step
is to break apart (denature) the double strands of DNA in both the probe
DNA and the chromosome DNA so they can bind to each other. This is done by
heating the DNA in a solution of formamide at a high temperature
(70-75.degree. C.) Next, the probe is placed on the slide and the slide is
placed in a 37.degree. C. incubator overnight for the probe to hybridize
with the target chromosome. Overnight, the probe DNA seeks out it's target
sequence on the specific chromosome and binds to it. The strands then
slowly reanneal. The slide is washed in a salt/detergent solution to
remove any of the probe that did not bind to chromosomes and differently
colored fluorescent dye is added to the slide to stain all of the
chromosomes so that they may then be viewed using a fluorescent light
microscope. Two, or more different probes labeled with different
fluorescent tags can be mixed and used at the same time. The chromosomes
are then stained with a third color for contrast. This gives a metaphase
or interphase cell with three or more colors which can be used to detect
different chromosomes at the same time, or to provide a control probe in
case one of the other target sequences are deleted and a probe cannot bind
to the chromosome. This technique allows, for example, the localization of
genes and also the direct morphological detection of genetic defects.
The advantage of using FISH probes over microsatellite instability to test
for loss of allelic heterozygosity is that the a) FISH is easily and
rapidly performed on cells of interest and can be used on
paraffin-embedded, or fresh or frozen tissue allowing the use of
micro-dissection b) specific gene changes can be analyzed on a cell by
cell basis in relationship to centomeric probes so that true homozygosity
versus heterozygosity of a DNA sequence can be evaluated (use of PCR for
microsatellite instability may permit amplification of surrounding normal
DNA sequences from contamination by normal cells in a homozygously deleted
region imparting a false positive impression that the allele of interest
is not deleted) c) PCR cannot identify amplification of genes d) FISH
using bacterial artificial chromosomes (BACs) permits easy detection and
localization on specific chromosomes of genes of interest which have been
isolated using specific primer pairs.
C. Template Dependent Amplification Methods
A number of template dependent processes are available to amplify the
marker sequences present in a given template sample. One of the best known
amplification methods is the polymerase chain reaction (referred to as
PCR.TM.) which is described in detail in U.S. Pat. Nos. 4,683,195,
4,683,202 and 4,800,159, and in Innis et al., 1990, each of which is
incorporated herein by reference in its entirety.
Briefly, in PCR, two primer sequences are prepared that are complementary
to regions on opposite complementary strands of the marker sequence. An
excess of deoxynucleoside triphosphates are added to a reaction mixture
along with a DNA polymerase, e.g., Taq polymerase. If the marker sequence
is present in a sample, the primers will bind to the marker and the
polymerase will cause the primers to be extended along the marker sequence
by adding on nucleotides. By raising and lowering the temperature of the
reaction mixture, the extended primers will dissociate from the marker to
form reaction products, excess primers will bind to the marker and to the
reaction products and the process is repeated.
A reverse transcriptase PCR amplification procedure may be performed in
order to quantify the amount of mRNA amplified. Methods of reverse
transcribing RNA into cDNA are well known and described in Sambrook et
al., 1989. Alternative methods for reverse transcription utilize
thermostable, RNA-dependent DNA polymerases. These methods are described
in WO 90/07641 filed Dec. 21, 1990. Polymerase chain reaction
methodologies are well known in the art.
Another method for amplification is the ligase chain reaction ("LCR"),
disclosed in EPO No. 320 308, incorporated herein by reference in its
entirety. In LCR, two complementary probe pairs are prepared, and in the
presence of the target sequence, each pair will bind to opposite
complementary strands of the target such that they abut. In the presence
of a ligase, the two probe pairs will link to form a single unit. By
temperature cycling, as in PCR, bound ligated units dissociate from the
target and then serve as "target sequences" for ligation of excess probe
pairs. U.S. Pat. No. 4,883,750 describes a method similar to LCR for
binding probe pairs to a target sequence.
Qbeta Replicase, described in PCT Application No. PCT/US87/00880, may also
be used as still another amplification method in the present invention. In
this method, a replicative sequence of RNA that has a region complementary
to that of a target is added to a sample in the presence of an RNA
polymerase. The polymerase will copy the replicative sequence that can
then be detected.
An isothermal amplification method, in which restriction endonucleases and
ligases are used to achieve the amplification of target molecules that
contain nucleotide 5'-[alpha-thio]-triphosphates in one strand of a
restriction site may also be useful in the amplification of nucleic acids
in the present invention, Walker et al., (1992).
Strand Displacement Amplification (SDA) is another method of carrying out
isothermal amplification of nucleic acids, which involves multiple rounds
of strand displacement and synthesis, i.e., nick translation. A similar
method, called Repair Chain Reaction (RCR), involves annealing several
probes throughout a region targeted for amplification, followed by a
repair reaction in which only two of the four bases are present. The other
two bases can be added as biotinylated derivatives for easy detection. A
similar approach is used in SDA. Target specific sequences can also be
detected using a cyclic probe reaction (CPR). In CPR, a probe having 3'
and 5' sequences of non-specific DNA and a middle sequence of specific RNA
is hybridized to DNA that is present in a sample. Upon hybridization, the
reaction is treated with RNase H, and the products of the probe identified
as distinctive products that are released after digestion. The original
template is annealed to another cycling probe and the reaction is
repeated.
Still another amplification methods described in GB Application No. 2 202
328, and in PCT Application No. PCT/US89/01025, each of which is
incorporated herein by reference in its entirety, may be used in
accordance with the present invention. In the former application,
"modified" primers are used in a PCR-like, template- and enzyme-dependent
synthesis. The primers may be modified by labeling with a capture moiety
(e.g., biotin) and/or a detector moiety (e.g., enzyme). In the latter
application, an excess of labeled probes are added to a sample. In the
presence of the target sequence, the probe binds and is cleaved
catalytically. After cleavage, the target sequence is released intact to
be bound by excess probe. Cleavage of the labeled probe signals the
presence of the target sequence.
Other nucleic acid amplification procedures include transcription-based
amplification systems (TAS), including nucleic acid sequence based
amplification (NASBA) and 3SR (Kwoh et al., 1989; Gingeras et al., PCT
Application WO 88/10315, incorporated herein by reference in their
entirety). In NASBA, the nucleic acids can be prepared for amplification
by standard phenol/chloroform extraction, heat denaturation of a clinical
sample, treatment with lysis buffer and minispin columns for isolation of
DNA and RNA or guanidinium chloride extraction of RNA. These amplification
techniques involve annealing a primer which has target specific sequences.
Following polymerization, DNA/RNA hybrids are digested with RNase H while
double stranded DNA molecules are heat denatured again. In either case the
single stranded DNA is made fully double stranded by addition of second
target specific primer, followed by polymerization. The double-stranded
DNA molecules are then multiply transcribed by an RNA polymerase such as
T7 or SP6. In an isothermal cyclic reaction, the RNA's are reverse
transcribed into single stranded DNA, which is then converted to double
stranded DNA, and then transcribed once again with an RNA polymerase such
as T7 or SP6. The resulting products, whether truncated or complete,
indicate target specific sequences.
Davey et al., EPO No. 329 822 (incorporated herein by reference in its
entirety) disclose a nucleic acid amplification process involving
cyclically synthesizing single-stranded RNA ("ssRNA"), ssDNA, and
double-stranded DNA (dsDNA), which may be used in accordance with the
present invention. The ssRNA is a template for a first primer
oligonucleotide, which is elongated by reverse transcriptase
(RNA-dependent DNA polymerase). The RNA is then removed from the resulting
DNA:RNA duplex by the action of ribonuclease H (RNase H, an RNase specific
for RNA in duplex with either DNA or RNA). The resultant ssDNA is a
template for a second primer, which also includes the sequences of an RNA
polymerase promoter (exemplified by T7 RNA polymerase) 5' to its homology
to the template. This primer is then extended by DNA polymerase
(exemplified by the large "Klenow" fragment of E. coli DNA polymerase I),
resulting in a double-stranded DNA ("dsDNA") molecule, having a sequence
identical to that of the original RNA between the primers and having
additionally, at one end, a promoter sequence. This promoter sequence can
be used by the appropriate RNA polymerase to make many RNA copies of the
DNA. These copies can then re-enter the cycle leading to very swift
amplification. With proper choice of enzymes, this amplification can be
done isothermally without addition of enzymes at each cycle. Because of
the cyclical nature of this process, the starting sequence can be chosen
to be in the form of either DNA or RNA.
Miller et al., PCT Application WO 89/06700 (incorporated herein by
reference in its entirety) disclose a nucleic acid sequence amplification
scheme based on the hybridization of a promoter/primer sequence to a
target single-stranded DNA ("ssDNA") followed by transcription of many RNA
copies of the sequence. This scheme is not cyclic, i.e., new templates are
not produced from the resultant RNA transcripts. Other amplification
methods include "RACE" and "one-sided PCR" (Frohman, M. A., In: PCR
PROTOCOLS: A GUIDE TO METHODS AND APPLICATIONS, Academic Press, N.Y.,
1990; Ohara et al., 1989; each herein incorporated by reference in their
entirety).
Methods based on ligation of two (or more) oligonucleotides in the
presence of nucleic acid having the sequence of the resulting "di-oligonucleotide",
thereby amplifying the di-oligonucleotide, may also be used in the
amplification step of the present invention. Wu et al., (1989),
incorporated herein by reference in its entirety.
D. Southern/Northern Blotting
Blotting techniques are well known to those of skill in the art. Southern
blotting involves the use of DNA as a target, whereas Northern blotting
involves the use of RNA as a target. Each provide different types of
information, although cDNA blotting is analogous, in many aspects, to
blotting or RNA species.
Briefly, a probe is used to target a DNA or RNA species that has been
immobilized on a suitable matrix, often a filter of nitrocellulose. The
different species should be spatially separated to facilitate analysis.
This often is accomplished by gel electrophoresis of nucleic acid species
followed by "blotting" on to the filter.
Subsequently, the blotted target is incubated with a probe (usually
labeled) under conditions that promote denaturation and rehybridization.
Because the probe is designed to base pair with the target, the probe will
binding a portion of the target sequence under renaturing conditions.
Unbound probe is then removed, and detection is accomplished as described
above.
E. Separation Methods
It normally is desirable, at one stage or another, to separate the
amplification product from the template and the excess primer for the
purpose of determining whether specific amplification has occurred. In one
embodiment, amplification products are separated by agarose,
agarose-acrylamide or polyacrylamide gel electrophoresis using standard
methods. See Sambrook et al., 1989.
Alternatively, chromatographic techniques may be employed to effect
separation. There are many kinds of chromatography which may be used in
the present invention: adsorption, partition, ion-exchange and molecular
sieve, and many specialized techniques for using them including column,
paper, thin-layer and gas chromatography (Freifelder, 1982).
F. Detection Methods
Products may be visualized in order to confirm amplification of the marker
sequences. One typical visualization method involves staining of a gel
with ethidium bromide and visualization under UV light. Alternatively, if
the amplification products are integrally labeled with radio- or
fluorometrically-labeled nucleotides, the amplification products can then
be exposed to x-ray film or visualized under the appropriate stimulating
spectra, following separation.
In one embodiment, visualization is achieved indirectly. Following
separation of amplification products, a labeled nucleic acid probe is
brought into contact with the amplified marker sequence. The probe
preferably is conjugated to a chromophore but may be radiolabeled. In
another embodiment, the probe is conjugated to a binding partner, such as
an antibody or biotin, and the other member of the binding pair carries a
detectable moiety.
In one embodiment, detection is by a labeled probe. The techniques
involved are well known to those of skill in the art and can be found in
many standard books on molecular protocols. See Sambrook et al., 1989. For
example, chromophore or radiolabel probes or primers identify the target
during or following amplification.
One example of the foregoing is described in U.S. Pat. No. 5,279,721,
incorporated by reference herein, which discloses an apparatus and method
for the automated electrophoresis and transfer of nucleic acids. The
apparatus permits electrophoresis and blotting without external
manipulation of the gel and is ideally suited to carrying out methods
according to the present invention.
In addition, the amplification products described above may be subjected
to sequence analysis to identify specific kinds of variations using
standard sequence analysis techniques. Within certain methods, exhaustive
analysis of genes is carried out by sequence analysis using primer sets
designed for optimal sequencing (Pignon et al, 1994). The present
invention provides methods by which any or all of these types of analyses
may be used. Using the sequences disclosed herein, oligonucleotide primers
may be designed to permit the amplification of sequences throughout the
RPL14, CD39L3, PMGM, or GC20 gene probes that may then be analyzed by
direct sequencing.
G. Kit Components
All the essential materials and reagents required for detecting and
sequencing RPL14, CD39L3, PMGM, or GC20 genes and variants thereof may be
assembled together in a kit. This generally will comprise preselected
primers and probes. Also included may be enzymes suitable for amplifying
nucleic acids including various polymerases (RT, Taq, Sequenase.TM. etc.),
deoxynucleotides and buffers to provide the necessary reaction mixture for
amplification. Such kits also generally will comprise, in suitable means,
distinct containers for each individual reagent and enzyme as well as for
each primer or probe.
H. Chip Technologies
Specifically contemplated by the present inventors are chip-based DNA
technologies such as those described by Hacia et al. (1996) and Shoemaker
et al. (1996). These techniques involve quantitative methods for analyzing
large numbers of genes rapidly and accurately. By tagging genes with
oligonucleotides or using fixed probe arrays, one can employ chip
technology to segregate target molecules as high density arrays and screen
these molecules using methods such as fluorescence, conductance, mass
spectrometry, radiolabeling, optical scanning, or electrophoresis. See
also Pease et al. (1994); Fodor et al. (1991).
Biologically active DNA probes may be directly or indirectly immobilized
onto a surface to ensure optimal contact and maximum detection. When
immobilized onto a substrate, the gene probes are stabilized and therefore
may be used repetitively. In general terms, hybridization is performed on
an immobilized nucleic acid target or a probe molecule is attached to a
solid surface such as nitrocellulose, nylon membrane or glass. Numerous
other matrix materials may be used, including reinforced nitrocellulose
membrane, activated quartz, activated glass, polyvinylidene difluoride (PVDF)
membrane, polystyrene substrates, polyacrylamide-based substrate, other
polymers such as poly(vinyl chloride), poly(methyl methacrylate),
poly(dimethyl siloxane), photopolymers (which contain photoreactive
species such as nitrenes, carbenes and ketyl radicals capable of forming
covalent links with target molecules (Saiki, et al., 1994).
Immobilization of the gene probes may be achieved by a variety of methods
involving either non-covalent or covalent interactions between the
immobilized DNA comprising an anchorable moiety and an anchor. DNA is
commonly bound to glass by first silanizing the glass surface, then
activating with carbodimide or glutaraldehyde. Alternative procedures may
use reagents such as 3-glycidoxypropyltrimethoxysilane (GOP) or
aminopropyltrimethoxysilane (APTS) with DNA linked via amino linkers
incorporated either at the 3' or 5' end of the molecule during DNA
synthesis. Gene probe may be bound directly to membranes using ultraviolet
radiation. With nitrocellous membranes, the probes are spotted onto the
membranes. A UV light source is used to irradiate the spots and induce
cross-linking. An alternative method for cross-linking involves baking the
spotted membranes at 80.degree. C. for two hours in vacuum.
Immobilization can consist of the non-covalent coating of a solid phase
with streptavidin or avidin and the subsequent immobilization of a
biotinylated polynucleotide (Holmstrom, 1993). Precoating a polystyrene or
glass solid phase with poly-L-Lys or poly L-Lys, Phe, followed by the
covalent attachment of either amino- or sulfhydryl-modified
polynucleotides using bifunctional crosslinking reagents (Running, 1990
and Newton, 1993) can also be used to immobilize the probe onto a surface.
Immobilization may also take place by the direct covalent attachment of
short, 5'-phosphorylated primers to chemically modified polystyrene plates
("Covalink" plates, Nunc) Rasmussen, (1991). The covalent bond between the
modified oligonucleotide and the solid phase surface is introduced by
condensation with a water-soluble carbodiimide. This method facilitates a
predominantly 5'-attachment of the oligonucleotides via their
5'-phosphates.
Nikiforov et al. (U.S. Pat. No. 5,610,287) describes a method of
non-covalently immobilizing nucleic acid molecules in the presence of a
salt or cationic detergent on a hydrophilic polystyrene solid support
containing an --OH, --C.dbd.O or --COOH hydrophilic group or on a glass
solid support. The support is contacted with a solution having a pH of
about 6 to about 8 containing the synthetic nucleic acid and the cationic
detergent or salt. The support containing the immobilized nucleic acid may
be washed with an aqueous solution containing a non-ionic detergent
without removing the attached molecules.
There are two common variants of chip-based DNA technologies involving DNA
microarrays with known sequence identity. For one, a probe cDNA
(500.about.5,000 bases long) is immobilized to a solid surface such as
glass using robot spotting and exposed to a set of targets either
separately or in a mixture. This method, "traditionally" called DNA
microarray, is widely considered as developed at Stanford University. A
recent article by Ekins and Chu (1999) provides some relevant details. The
other variant includes an array of oligonucleotide (20.about.25-mer oligos)
or peptide nucleic acid (PNA) probes is synthesized either in situ
(on-chip) or by conventional synthesis followed by on-chip immobilization.
The array is exposed to labeled sample DNA, hybridized, and the
identity/abundance of complementary sequences are determined. This method,
"historically" called DNA chips, was developed at Affymetrix, Inc., which
sells its products under the GeneChip.RTM. trademark.
Claim 1 of 26 Claims
1. A method for identifying a subject at
risk for the development of non-small cell lung cancer comprising: (a)
obtaining a test sample from a human subject; (b) providing a 3p21 DNA
probe selected from a CD39L3, PMGM, or GC20 gene probe; (c) contacting the
probe with the test sample; (d) analyzing DNA from the test sample, (e)
detecting a loss of heterozygosity in the hybridization of the probe to
the DNA, as compared to a centromeric DNA probe for chromosome 3; and (f)
identifying the subject at risk for the development of non-small cell lung
cancer when loss of heterozygosity is detected.
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