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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recent evidence obtained by in situ hybridization indicates that chromosomal region 17q is often lost in prostate tumors. To substantiate the presence of tumor suppressor genes in this chromosomal region, normal human 17q tagged with a neomycin resistance gene was transferred into a human prostate cancer cell line, PPC-1, by microcell-mediated chromosome transfer. Two hybrid clones were obtained, both of which showed decreased tumorigenicity in athymic nude mice and decreased efficiency of colony formation in soft agar with respect to PPC-1. When microcells were irradiated prior to transfer of chromosomal region 17q to determine which subchromosomal regions carry the potential tumor suppressor gene(s), 10 hybrid clones were obtained, including 6 fully malignant and 4 suppressed clones. Analysis of polymorphic loci on 17q in the series of hybrid clones suggested that a tumor suppressor gene associated with prostate cancer was located in a region no more than 28 cM long at 17q12-q22, which includes the BRCA1 gene involved in hereditary breast cancer.
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PMID:Suppression of malignant phenotype in a human prostate cancer cell line by fragments of normal chromosomal region 17q. 761 77

A familial early onset breast cancer gene (BRCA1) has been localized to chromosome 17q21. To aid in the identification of this gene a number of new microsatellite markers from the D17S857 to D17S78 region were isolated and characterized. These markers, along with previously published markers from the region, were localized on a physical map by STS content mapping of cosmids from the BRCA1 interval. This high-density STS map of the BRCA1 region will be useful for linkage studies of families with apparent inherited breast cancer and for loss of heterozygosity analysis of breast tumor DNAs.
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PMID:Characterization of 10 new polymorphic dinucleotide repeats and generation of a high-density microsatellite-based physical map of the BRCA1 region of chromosome 17q21. 771 91

This review discusses recent insights into the roles of the p53 tumor-suppressor gene and growth factors in the development of ovarian cancer and describes the genes implicated in familial ovarian cancer syndromes related to the MSH2 (Lynch II) and BRCA1 (breast and ovarian cancer) genes. Evidence of the monoclonality of ovarian cancer, which contrasts with data supporting the polyclonal origin of primary peritoneal carcinoma, is presented. Finally, the roles of the human papillomavirus and the HIV virus in the etiology of cervical cancer are analyzed in view of the growing importance of this HIV-associated cancer and the poor outcome in these patients.
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PMID:Advances in the biology of gynecologic cancer. 782 56

The VH1-related human protein (VHR) gene was localized to human chromosome 17q21 in a region thought to contain the BRCA1 locus, a locus that confers susceptibility to breast and ovarian cancer. VHR encodes a phosphatase with dual specificity for tyrosine and serine residues. Thus it is a plausible candidate for a tumor suppressor gene such as BRCA1. To test this possibility, the VHR coding sequence was screened in individuals with familial breast cancer and in sporadic breast tumor and breast cancer cell lines. No mutations were detected, suggesting that the VHR gene is not BRCA1.
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PMID:Localization of the VHR phosphatase gene and its analysis as a candidate for BRCA1. 782 67

A number of candidate tumor suppressor genes located on the human chromosome 17 are thought to have a role to play in the development of breast cancer. In addition to the p53 gene on 17p13.1 and the BRCA1 gene mapped to 17q12-21, other chromosomal regions for tumor suppressor genes have been suggested to exist on 17p13.3 and both the central and the distal parts of 17q, although definitive functional proof of their involvement in breast cancer tumorigenesis is still lacking. In this report we show that microcell transfer of a human chromosome 17 into wild-type p53 breast cancer cells CAL51 results in loss of tumorigenicity and anchorage-independent growth, changes in cell morphology and a reduction of cell growth rates of the neo-selected microcell hybrids. In the hybrid cells, which express the p53 wild-type protein, only the p- and the distal parts of the q arm of donor chromosome 17 are transferred. Thus, our results provide functional evidence for the presence of one or more tumor suppressor gene(s) on chromosome 17, which are distinct from the p53 and the BRCA1 genes.
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PMID:Suppression of tumorigenicity of breast cancer cells by transfer of human chromosome 17 does not require transferred BRCA1 and p53 genes. 784 68

Loss of heterozygosity data from familial tumors suggest that BRCA1, a gene that confers susceptibility to ovarian and early-onset breast cancer, encodes a tumor suppressor. The BRCA1 region is also subject to allelic loss in sporadic breast and ovarian cancers, an indication that BRCA1 mutations may occur somatically in these tumors. The BRCA1 coding region was examined for mutations in primary breast and ovarian tumors that show allele loss at the BRCA1 locus. Mutations were detected in 3 of 32 breast and 1 of 12 ovarian carcinomas; all four mutations were germline alterations and occurred in early-onset cancers. These results suggest that mutation of BRCA1 may not be critical in the development of the majority of breast and ovarian cancers that arise in the absence of a mutant germline allele.
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PMID:BRCA1 mutations in primary breast and ovarian carcinomas. 793 30

Linkage analysis in familial breast and ovarian cancer and studies of allelic deletion in sporadic ovarian tumors have identified a region on chromosome 17q containing a candidate tumor-suppressor gene (referred to as BRCA1) of likely importance in ovarian carcinogenesis. We have examined normal and tumor DNA samples from 32 patients with sporadic and 8 patients with familial forms of the disease, for loss of heterozygosity (LOH) at 21 loci on chromosome 17 (7 on 17p and 14 on 17q). LOH on 17p was 55% (22/40) for informative 17p13.1 and 17p13.3 markers. When six polymorphic markers flanking the familial breast/ovarian cancer susceptibility locus on 17q12-q21 were used, LOH was 58% (23/40), with one tumor showing telomeric retention. Evaluation of a set of markers positioned telomeric to BRCA1 resulted in the highest degree of LOH, 73% (29/40), indicating that a candidate locus involved in ovarian cancer may reside distal to BRCA1. Five of the tumors demonstrating allelic loss for 17q markers were from individuals with a strong family history of breast and ovarian cancer. More important, two of these tumors (unique patient number [UPN] 57 and UPN 79) retained heterozygosity for all informative markers spanning the BRCA1 locus but showed LOH at loci distal to but not including the anonymous markers CMM86 (D17S74) and 42D6 (D17S588), respectively. Deletion mapping of seven cases (two familial and five sporadic) showing limited LOH on 17q revealed a common region of deletion, distal to GH and proximal to D17S4, that spans approximately 25 cM. These results suggest that a potential tumor-suppressor gene involved in both sporadic and familial ovarian cancer may reside on the distal portion of chromosome 17q and is distinct from the BRCA1 gene.
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PMID:A common region of deletion on chromosome 17q in both sporadic and familial epithelial ovarian tumors distal to BRCA1. 794 44

BRCA1, a breast-ovarian cancer susceptibility gene which has been localized to 17q21, appears to be a tumor suppressor gene based on evidence from loss of heterozygosity (LOH) studies. We analyzed 14 ovarian and breast tumors from BRCA1 carriers and 1 sporadic breast tumor from 3 kindreds for 17q21 LOH. Thirteen of the 14 tumors from gene carriers exhibited LOH of the wild-type allele. Tumors from one gene carrier and the sporadic breast case did not exhibit any LOH in the region. There was loss of the wild-type allele from both maternally and paternally derived chromosomes, therefore excluding the possibility of genomic imprinting and providing further evidence that BRCA1 is a tumor suppressor. Three tumors showed interstitial LOH in the region, and thus established the utility of familial tumors in refining a region surrounding a tumor suppressor gene in a manner analogous to using genetic recombinants.
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PMID:Loss of heterozygosity in familial tumors from three BRCA1-linked kindreds. 795 48

Multiple specific chromosomal deletions can be found in human epithelial ovarian cancer by cytogenetic analysis or molecular techniques. Somatic allelic deletion or loss of heterozygosity (LOH) in a tumor is considered circumstantial evidence for the location of tumor suppressor genes. We have examined 27 primary epithelial ovarian tumors for the presence of LOH at 19 polymorphic markers on chromosomes 1, 5, 6, 9, 11, 13, and 17. Markers near the adenomatous polyposis coli (APC) gene at 5q21 showed LOH in 50% (10/20) of informative cases. LOH was seen in 53% (8/15) at the IFNA locus on 9p, another region implicated in other tumors, but not previously associated with ovarian cancer. We observed LOH for markers on 11p15 in 50% (12/24) of ovarian cancer DNAs from informative cases, while only 25% (4/16) at 11q13 and 29% (5/17) at 11q24 showed LOH. Only a portion of distal 11p was deleted in six cases. The incidence of LOH (50%) at HGH (17q22-q24) was greater than that at D17S579 (39%; 17q21), a locus tightly linked to BRCA1. Sixty-four percent (7/11) showed allelic loss at 17p11. LOH was infrequently observed at markers on chromosomes 1, 6, and 13q. Most cases showing LOH were stage III or IV, and most showed LOH at more than one locus. These studies support the concept that multiple genetic loci are involved in ovarian tumorigenesis. Two additional regions thought to harbor genes important in other cancers, 5q21 and 9p21, can now be added to the growing spectrum of molecular alterations seen in ovarian cancer.
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PMID:Molecular genetic changes associated with ovarian cancer. 795 92

BRCA1, a gene predisposing to breast and ovarian cancer, was mapped to chromosome 17q21 by linkage analysis. Loss of heterozygosity in breast and ovarian tumors from BRCA1-linked patients always involved loss of wild-type alleles from chromosome 17q21, suggesting that BRCA1 acts as a tumor suppressor gene. Meiotic recombination in linked families constrained the BRCA1 region to an estimated physical size of 650 kilobases. Twenty-two candidate genes were isolated by screening complementary DNA libraries with yeast artificial chromosomes and cosmids from the critical region. Of these, 8 were known human genes, 7 were homologues of genes identified in other species, and 7 encoded novel transcripts. Each gene were sequenced and analyzed for variation, revealing 44 variants, including two missense mutations in two genes which segregated with breast cancer and were not found in controls. However, no frame-shift, nonsense, or regulatory mutations were found.
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PMID:The search for BRCA1. 798 31


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