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D Sidransky

Publications and source records attributed to D Sidransky.

At least 91 records · Page 5Linked to original sources
PubMed1999

Detection of adenocarcinoma by urinary microsatellite analysis after augmentation cystoplasty.

Augmentation cystoplasty is associated with an increased risk of bladder cancer development between 10 and 20 years after augmentation. Using microsatellite analysis, we analyzed urine obtained before surgical resection of the malignant lesion from a patient who developed invasive adenocarcinoma after augmentation cystoplasty. Loss of heterozygosity was identified in both urine and tumor samples from this patient. This observation suggests that microsatellite urine analysis may be useful as a monitoring tool for patients after augmentation cystoplasty.

Adenocarcinoma↗
PubMed1999

Head and neck cancer in nonsmokers: a distinct clinical and molecular entity.

OBJECTIVES/HYPOTHESIS: Clinical and molecular patterns of head and neck squamous cell carcinoma (HNSCC) in nonsmokers and smokers may be different. Analysis of these patterns may improve understanding and management of this disease. STUDY DESIGN: three hundred five subjects were included (46 nonsmokers, 29 former smokers, and 230 smokers). Subsets were analyzed for p53 mutation, human papillomavirus (HPV), and loss of heterozygosity (LOH) at 10 chromosomal loci. METHODS: Clinical information was analyzed for common patterns of disease among the groups. The p53 gene was sequenced, and polymerase chain reaction was used to detect HPV DNA and LOH at two microsatellite markers for each loci. The chi2 test was used to assess differences in genetic alterations between groups, logistic regression to examine the independence of association of tobacco exposure with each alteration, and Kaplan Meier estimates and the log-rank statistic to assess differences in survival. RESULTS: Nonsmokers included a disproportionate number of women, oral cavity (especially tongue) tumors, and very young or old individuals. Smokers had more tumors of the larynx, hypopharynx, and floor of mouth. The rate of p53 mutation was much greater in smokers; the percentage with HPV was marginally lower. The percentage of LOH at 3p, 4q, and 11q13, and the overall average number of chromosomal losses, was significantly lower in nonsmokers' tumors. Survival did not vary with smoking or age. CONCLUSIONS: The clinical and genetic features of HNSCC are distinct between groups defined by tobacco use. Tumors of nonsmokers contain a lower frequency of common genetic alterations, suggesting that the underlying changes in these tumors may remain undiscovered.

Adolescent↗
PubMed1999

Analysis of p16 (CDKN2/MTS-1/INK4A) alterations in primary sporadic uveal melanoma.

PURPOSE: To define more clearly the role of the tumor suppressor gene p16 in uveal melanoma by determining the relative contribution of all known mechanisms of p16 inactivation in this tumor. METHODS: A comprehensive genetic analysis of the p16 gene was performed in 33 primary sporadic ciliochoroidal and choroidal melanomas. Fourteen highly polymorphic microsatellite markers surrounding the p16 locus on chromosome 9p21 were used for the microsatellite analysis. Sequence analysis of the p16 gene was performed on those tumors with 9p21 loss of heterozygosity. To investigate methylation as an alternative mechanism of inactivation of p16, methylation-specific polymerase chain reaction was performed on all tumor DNA samples. RESULTS: Loss of heterozygosity (LOH) was found in 8 of 33 (24%) uveal melanomas. No evidence of a second region of LOH that did not include the p16 locus was found. Four cases had hemizygous losses including markers both distal and proximal to p16. Homozygous deletion of the p16 gene was detected in the 4 remaining cases by microsatellite analysis. Sequence analysis revealed no p16 mutations in the tumors with hemizygous loss of p16. Methylation of the 5' CpG island of p16 was found in one tumor with 9p21 LOH and in another without LOH. CONCLUSIONS: p16 inactivation by HD or methylation occurs in 27% of uveal melanomas, representing the most common molecular genetic alteration identified thus far in uveal melanoma.

Chromosomes, Human, Pair 16↗
PubMed1999

Second esophageal tumors in patients with head and neck squamous cell carcinoma: an assessment of clonal relationships.

Patients with squamous cell carcinoma of the head and neck (HNSCC) often develop second carcinomas elsewhere in the upper aerodigestive tract. Some of these paired tumors share a common origin, reflecting the ability of a single progenitor cell to replicate, expand, and populate contiguous regions of the upper aerodigestive tract-a process referred to as clonal expansion. The geographical limitations of clonal expansion, however, have not been adequately addressed. For example, it is not known whether a neoplastic clone from the oral cavity, pharynx, or larynx can migrate to the esophagus. We compared paired tumors from 16 patients with HNSCC and a second squamous cell carcinoma of the esophagus (ESCC) for patterns of allelic loss on chromosomal arms 3p, 9p, and 17p. Losses at these loci occur early during neoplastic transformation of the respiratory tract. In 14 cases (87%), the paired tumors had discordant patterns of allelic loss, suggesting that these tumors were not clonally related. Conversely, two (13%) of the 16 paired tumors had identical genetic alterations, which suggests clonal expansion as the mechanism underlying tumor multifocality. One clone spread from the hypopharynx into the cervical esophagus, and the other spread from the tonsil to the distal esophagus. Although most second ESCCs appear to arise as independent neoplasms, a clonal population of neoplastic cells is capable of traveling across substantial distances to give rise to second tumors at different anatomical sites.

Carcinoma, Squamous Cell↗
PubMed1999

The potential of molecular screening.

Clonal genetic alterations such as tumor suppressor, gene mutations, or microsatellite instability are a hallmark of human cancer. These genetic alterations can be detected in clinical samples using DNA amplification techniques and used for early detection of cancer. This article reviews molecular-based approaches for screening of malignancies commonly encountered by the practicing general surgeon.

Biomarkers, Tumor↗
PubMed1999

Molecular detection of neoplastic cells in lymph nodes of metastatic colorectal cancer patients predicts recurrence.

Disseminated disease, especially to the liver, constitutes the major risk of recurrence for colorectal cancer patients. However, successful resection can still be achieved in 25-35% of colorectal cancer patients with isolated metastases. To evaluate the clinical value of occult micrometastatic disease detection in lymph nodes, we tested genetic (K-ras and p53 gene mutations) and epigenetic (p16 promoter hypermethylation) molecular markers in the perihepatic lymph nodes from colorectal cancer patients with isolated liver metastases. DNA was extracted from 21 paraffin-embedded liver metastases and 80 lymph nodes from 21 colorectal cancer patients. K-ras and p53 gene mutations were identified in DNA from liver metastases by PCR amplification followed by cycle sequencing. A sensitive oligonucleotide-mediated mismatch ligation assay was used to search for the presence of K-ras and p53 mutations to detect occult disease in 68 lymph nodes from tumors positive for these gene mutations. Promoter hypermethylation at the p16 tumor suppressor gene was examined in both liver lesions and lymph nodes by methylation-specific PCR. Sixteen of the 21 (76%) liver metastases harbored either gene point mutations or p16 promoter hypermethylation. Twelve of the 68 lymph nodes were positive for tumor cells by molecular evaluation and negative for tumor cells by histopathology and cytokeratin immunohistochemistry, whereas none were positive for tumor cells by histopathology or negative for tumor cells by molecular analysis (P = 0.0005, McNemar's test). Moreover, in three patients with lymph nodes that were histologically negative at all sites, molecular screening detected tumor DNA at one or more lymph nodes. Survival analysis showed a median survival of 1056 days for patients without evidence of lymph node involvement by molecular analysis and 165 days for patients with positive lymph nodes by this approach (P = 0.0005). These results indicate that lymph node metastasis screening in colorectal cancer patients by molecular-based techniques increases the sensitivity of tumor cell detection and can be a good predictor of recurrence in colorectal cancer patients with resectable liver metastases.

Colorectal Neoplasms↗
PubMed1998

Serial analysis of gene expression in non-small cell lung cancer.

We used the serial analysis of gene expression (SAGE) method to systematically analyze transcripts present in non-small cell lung cancer. Over 226,000 SAGE tags were sequence analyzed from two independent primary lung cancers and two normal human bronchial/tracheal epithelial cell cultures. A total of 226,000 SAGE tags were sequence identified, representing 43,254 unique transcripts. Comparison of the tags present in the tumor with those identified in the normal tissue revealed 175 transcript tags that were overrepresented in the normal tissue and 142 tags that were overexpressed in the tumor by 10-fold or more. Northern hybridization was performed on 15 of the most abundantly expressed tags identified in the tumors. These tags were derived from either a known gene or a matched expressed sequence tag clone. The transcripts for 3 of the 15 genes, PGP 9.5, B-myb, and human mutT, were abundantly expressed in primary lung cancers (10 of 18, 15 of 18, and 6 of 12 tumors, respectively). In contrast, the presence of PGP9.5 and B-myb was much less frequent in primary tumors derived from other tissue origins. These results suggest that at least a portion of the transcripts identified by SAGE are frequently associated with lung cancer, and that their overexpression may contribute to lung tumorigenesis. The identification and further characterization of genes generated by SAGE should provide potential new targets for the diagnosis, prognosis, and therapy of lung cancer.

Bronchi↗
PubMed1998

A National Cancer Institute Workshop on Microsatellite Instability for cancer detection and familial predisposition: development of international criteria for the determination of microsatellite instability in colorectal cancer.

In December 1997, the National Cancer Institute sponsored "The International Workshop on Microsatellite Instability and RER Phenotypes in Cancer Detection and Familial Predisposition," to review and unify the field. The following recommendations were endorsed at the workshop. (a) The form of genomic instability associated with defective DNA mismatch repair in tumors is to be called microsatellite instability (MSI). (b) A panel of five microsatellites has been validated and is recommended as a reference panel for future research in the field. Tumors may be characterized on the basis of: high-frequency MSI (MSI-H), if two or more of the five markers show instability (i.e., have insertion/deletion mutations), and low-frequency MSI (MSI-L), if only one of the five markers shows instability. The distinction between microsatellite stable (MSS) and low frequency MSI (MSI-L) can only be accomplished if a greater number of markers is utilized. (c) A unique clinical and pathological phenotype is identified for the MSI-H tumors, which comprise approximately 15% of colorectal cancers, whereas MSI-L and MSS tumors appear to be phenotypically similar. MSI-H colorectal tumors are found predominantly in the proximal colon, have unique histopathological features, and are associated with a less aggressive clinical course than are stage-matched MSI-L or MSS tumors. Preclinical models suggest the possibility that these tumors may be resistant to the cytotoxicity induced by certain chemotherapeutic agents. The implications for MSI-L are not yet clear. (d) MSI can be measured in fresh or fixed tumor specimens equally well; microdissection of pathological specimens is recommended to enrich for neoplastic tissue; and normal tissue is required to document the presence of MSI. (e) The "Bethesda guidelines," which were developed in 1996 to assist in the selection of tumors for microsatellite analysis, are endorsed. (f) The spectrum of microsatellite alterations in noncolonic tumors was reviewed, and it was concluded that the above recommendations apply only to colorectal neoplasms. (g) A research agenda was recommended.

Colorectal Neoplasms↗
PubMed1998

Rare loss-of-function mutation of a death receptor gene in head and neck cancer.

The chromosomal region 8p21 contains a number of putative tumor suppressor genes and is a frequent site of translocations in head and neck cancers. Recently, a novel tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) death receptor gene, KILLER/DR5, a member of the tumor necrosis factor receptor family, was identified as a potential mediator in p53-dependent apoptosis and mapped to 8p21 by fluorescence in situ hybridization. We have determined the genomic structure of KILLER/DR5 and performed sequence analysis of all 10 coding exons in 20 primary head and neck cancers with allelic loss of chromosome 8p. To screen for a subset of mutations localized to the functional cytoplasmic death domain, we sequenced this region in an additional 40 primary head and neck cancers. We found two alterations in this domain, including a 2-bp insertion at a minimal repeat site, introducing a premature stop codon and resulting in a truncated protein. This KILLER/DR5 mutation was also present in the germ line of the affected patient, and the tumor did not have a p53 mutation by sequence analysis. Transfection studies in head and neck squamous cell carcinoma and colon and ovarian carcinoma cell lines revealed loss of growth-suppressive function associated with the tumor-derived KILLER/DR5 truncation mutant. These observations provide the first evidence for mutation of a TRAIL death receptor gene in a human cancer, leading to loss of its apoptotic function.

Base Sequence↗
PubMed1998

Distinguishing second primary tumors from lung metastases in patients with head and neck squamous cell carcinoma.

BACKGROUND: In patients with head and neck squamous cell carcinoma (HNSCC), a squamous cell carcinoma (SCC) in the lung represents either another primary tumor or a metastasis. This distinction greatly influences patient prognosis and could guide treatment strategies, but the nature of a solitary lung nodule is often difficult to discern by use of standard clinical and histologic parameters. Comparison of genetic alterations in the tumors could resolve this dilemma. METHODS: We compared paired tumors from 16 patients with HNSCC and a solitary lung SCC for loss (i.e., deletion) of loci on chromosomal arms 3p and 9p. Losses at these loci occur early during neoplastic transformation of the respiratory tract. DNA from microdissected tumors and normal tissues was subjected to polymerase chain reaction-based microsatellite analysis. An effort was also made to distinguish primary lung cancers from lung metastases on the basis of clinical and histopathologic features. RESULTS: In most cases, comparison of genetic alterations clarified the relationship between the lung tumor and the primary HNSCC. The paired tumors from 10 patients had concordant patterns of loss at all loci suggesting metastatic spread, whereas three paired tumors had discordant patterns of loss at all loci suggesting independent tumor origin. These observations were supported by the clinical and pathologic findings. CONCLUSIONS/IMPLICATIONS: In patients with HNSCC and a solitary SCC in the lung, microsatellite analysis provides a rapid genetic approach for discerning clonal relationships. In such patients, we found that a solitary SCC in the lung more likely represents a metastasis than an independent lung cancer. Microsatellite analysis could potentially be applied to any patient with multiple tumors, where tumor relationships are not clear on clinical, radiographic, or even histopathologic grounds.

Adult↗
PubMed1998

Point mutation and homozygous deletion of PTEN/MMAC1 in primary bladder cancers.

A new tumor suppressor gene PTEN/MMAC1 was recently isolated at chromosome 10q23 and found to be inactivated by point mutation or homozygous deletion in glioma, prostate and breast cancer. PTEN/MMAC1 was also identified as the gene predisposing to Cowden disease, an autosomal dominant cancer predisposition syndrome associated with an increased risk of breast, skin and thyroid tumors and occasional cases of other cancers including bladder and renal cell carcinoma. We screened 345 urinary tract cancers by microsatellite analysis and found chromosome 10q to be deleted in 65 of 285 (23%) bladder and 15 of 60 (25%) renal cell cancers. We then screened the entire PTEN/MMAC1 coding region for mutation in 25 bladder and 15 renal cell primary tumors with deletion of chromosome 10q. Two somatic point mutations, a frameshift and a splicing variant, were found in the panel of bladder tumors while no mutation was observed in the renal cell carcinomas. To screen for homozygous deletion, we isolated two polymorphic microsatellite repeats from genomic BAC clones containing the PTEN/MMAC1 gene. Using these new informative markers, we identified apparent retention at the gene locus indicative of homozygous deletion of PTEN/MMAC1 in four of 65 bladder and 0 of 15 renal cell tumors with LOH through chromosome 10q. Identification of the second inactivation event in six bladder tumors with LOH of 10q implies that the PTEN/MMAC1 gene is occasionally involved in bladder tumorigenesis. However, the low frequency of biallelic inactivation suggests that either PTEN/MMAC1 is inactivated by other mechanisms or it is not the only target of chromosome 10q deletion in primary bladder and renal cell cancer.

Base Sequence↗
PubMed1998

Absence of TSG101 transcript abnormalities in human cancers.

The human TSG101 gene was cloned and mapped to chromosome 11p15, a site suspected to contain a tumor suppressor gene involved in a variety of human cancers. Subsequent investigation described the presence of abnormally spliced transcripts and point mutations of TSG101 in breast cancer. Thus, we performed RT-PCR amplification of the entire open reading frame of TSG101 to test for aberrant transcripts in various human tumor cell lines derived from breast, bladder, head and neck, and lung cancer. In addition, we performed RT-PCR on cDNA from primary human breast and Wilms' tumor tissue. We found a single band of the expected size in 10 of 11 breast cancers and 6 of 6 Wilms' tumor samples after the first round of PCR. The remaining breast cancer sample displayed a barely visible smaller band. However, aberrant bands appeared in most cases after performing nested PCR casting doubt on the physiologic relevance of these spliced variants. We then searched for small intragenic mutations by complete sequence analysis of TSG101 in breast cancer cell lines and tumors, as well as in Wilms' tumors and normal fetal and adult kidney. No point mutations were found in any of the samples, including four breast tumors with chromosomal loss at 11p15. We found no consistent evidence of aberrant splicing or point mutations in breast cancer or Wilms' tumor suggesting that TSG101 is not a primary target of inactivation in human cancer.

Adult↗
PubMed1998

Molecular detection of genetic alterations in the serum of colorectal cancer patients.

We have searched for the presence of genetic alterations in serum DNA obtained from 44 colorectal cancer patients. Microsatellite analysis using highly polymorphic markers revealed loss of heterozygosity and/or microsatellite instability in 35 of 44 (80%) primary tumors. No alterations were detected in the paired serum DNA. We next used an oligonucleotide-mediated mismatch ligation assay to detect tumor specific gene mutations in the serum. Among the 16 cases with a K-ras gene mutation in the tumor, the same mutation was detected in three paired serum samples. In the 10 cases with a p53 mutation in the tumor, the identical mutation was detected in seven corresponding serum samples. Comparison of the molecular analysis with clinical diagnosis of these patients revealed that none of the seven Dukes' stage B patients with a K-ras mutation in their tumors demonstrated a mutation in the serum. In contrast, five of seven stage B patients with a p53 mutation in the tumor demonstrated a mutation in the paired serum (P = 0.01, Fisher's exact test). Taken together, either a K-ras or p53 mutation was detected in the serum in 40% of the 25 patients (95% confidence interval, 21-61%), whose primary tumors contained a mutation and in 23% of the 44 patients (95% confidence interval, 12-38%) with colorectal cancer. The frequent detection of p53 mutation in the serum of patients with early stage tumors suggests a possible use of this approach for clinical prognosis and cancer monitoring of colorectal cancer patients.

Alleles↗
PubMed1998

Analysis of PTEN/MMAC1 alterations in aerodigestive tract tumors.

PTEN/MMAC1 is a candidate tumor suppressor gene recently identified at chromosomal band 10q23. It is mutated in sporadic brain, breast, and prostate cancer and in the germ line of patients with hereditary Cowden disease. We searched for genetic alterations of the PTEN/MMAC1 gene in 39 primary head and neck cancers (HNSCCs), 42 primary non-small cell lung cancers (NSCLCs), 80 pancreatic cancer xenografts, and 37 cell lines and xenografts from colon, lung, and gastric cancers. Microsatellite analysis revealed loss of heterozygosity at markers near the gene in 41% of primary HNSCCs, 50% of NSCLCs, and 39% of the pancreatic cancers. Three cases of HNSCCs displayed homozygous deletion involving the gene. We sequenced the entire coding region of the PTEN/MMAC1 gene in the remaining tumors displaying loss of heterozygosity and found one terminating mutation in a HNSCC sample. Thus, a second inactivation event was observed in 4 of 39 primary HNSCC cases. By use of a protein truncation assay, one terminating mutation was also identified in one of eight NSCLC cell lines. Our results suggest that PTEN/MMAC1 gene inactivation plays a role in the genesis of some tumor types.

Carcinoma, Non-Small-Cell Lung↗
PubMed1998

Interfocal heterogeneity of PTEN/MMAC1 gene alterations in multiple metastatic prostate cancer tissues.

The long arm of chromosome 10 is frequently affected by allelic loss in prostate cancer. PTEN/MMAC1, a candidate tumor suppressor gene located at 10q23.3, a region commonly deleted in prostate cancer, was recently identified and found to be deleted or mutated in cancer cell lines derived from a variety of human tissues including prostate. To examine the role of PTEN/MMAC1 in the progression of prostate cancer, we screened a unique set of 50 metastatic prostate cancer tissues from 19 cancer-death patients for alterations in the PTEN/MMAC1 gene, using single-strand conformational polymorphism analysis and direct sequencing to identify sequence changes and microsatellite analysis to examine allelic loss in the vicinity of PTEN/MMAC1. Overall, gene alterations (deletions or point mutations) were observed in at least 1 metastatic site in 12 of the 19 patients studied. Two cases had homozygous deletions that were confirmed by fluorescence in situ hybridization analysis. Four patients harbored point mutations, with one mutation being found in all four tumors (a primary lesion and three different metastases) from the same patient. The remaining three mutations were detected in only one of multiple metastases. Loss of heterozygosity was found in 10 of 18 informative cases, with 1 case showing a unique pattern of microsatellite instability in each of six different metastases examined. Loss of the same allele was found in all metastases in a given patient in 9 of 10 cases. These results indicate that PTEN/MMAC1 gene alterations occur frequently in lethal prostate cancer, although a substantial amount of mutational heterogeneity is found among different metastatic sites within the same patient. These latter findings emphasize the potentially complex genetic relationship that can exist between various clonal lineages of prostate cancer cells as they evolve during the metastatic process and suggest a molecular basis for phenotypic heterogeneity of different prostate cancer foci in patients with disseminated disease.

Aged↗
PubMed1998

Somatic mutations of the PTEN tumor suppressor gene in sporadic follicular thyroid tumors.

The PTEN (MMAC1/TEP1) tumor suppressor gene was recently isolated and mapped to human chromosome band 10q23. Homozygous deletions and mutations of PTEN were observed in cell lines and sporadic cancers of the breast, kidney, and central nervous system. Germline mutations in PTEN were recently found in Cowden disease, an autosomal dominant inherited syndrome, previously mapped to chromosome bands 10q22-23. This disease is associated with a wide variety of malignancies and hamartomas of ectodermal, mesodermal, and endodermal origin. The most common neoplasms in Cowden disease patients arise in the breast, skin, and thyroid (follicular subtype). To determine the involvement of PTEN in sporadic follicular thyroid tumors, we first analyzed sporadic follicular adenomas and carcinomas for deletions of the PTEN gene. Loss of heterozygosity was found in 7/26 (27%) follicular carcinomas and 2/27 (7%) follicular adenomas, one of which was a small hemizygous deletion (approximately 3 cm). Sequence analysis of the entire PTEN coding region revealed two mutations in carcinomas with 10q loss. Our findings suggest that the PTEN tumor suppressor gene is occasionally inactivated in sporadic follicular thyroid tumors.

Adenocarcinoma, Follicular↗
PubMed1998

Lack of BRCA2 alterations in primary head and neck squamous cell carcinoma.

We previously demonstrated that loss of 13q occurred in greater than 50% of primary head and neck squamous cell carcinomas. Although the minimal region of loss at 13q14.1-14.3 included the Rb1 gene, Rb1 inactivation was found to be rare. To further investigate possible targets of 13q loss in head and neck cancer, 32 primary tumors were fine mapped by microsatellite analysis with the use of 10 new markers spanning the minimal region. Twenty-one (66%) of 32 tumors displayed loss of heterozygosity and once again the minimal region of loss was confirmed to be 13q14.1-14.3. In addition to 6 monosomies, 11 tumors had regions of loss that either selectively deleted (one tumor) or stretched into the BRCA2 region 13q12-13 (10 tumors). Therefore we pursued investigation of the BRCA2 gene by a coupled transcription and translation assay of its largest exon (exon 11; 4932 base pairs) to detect functional truncations indicative of mutation in 37 primary head and neck tumors with 13q loss. These tumors included 17 of the 32 tumors recently analyzed and 20 other tumors with 13q loss from a previous study. Additionally, we performed the transcription and translation assay on five head and neck cancer cell lines. We found no alterations in exon 11 of the BRCA2 gene in any of the tumors or cell lines suggesting that perhaps another tumor suppressor gene on 13q is involved in head and neck cancer.

BRCA2 Protein↗