Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0677930 (primary tumor)
 20,210 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

There is a clear association between germ-line BRCA1 mutations and inherited ovarian cancer; however, the association between BRCA1 mutations and sporadic ovarian cancer remains ambiguous. The frequency of BRCA1 promoter hypermethylation as an epigenetic means of BRCA1 inactivation was determined for a large, population-based cohort of ovarian cancer patients. BRCA1 promoter hypermethylation was determined by methylation-specific restriction digestion of tumor DNA, followed by Southern blot analysis and confirmed by methylation-specific PCR. BRCA1 promoter hypermethylation was observed in 12 of 98 ovarian tumors. BRCA1 methylation status of the primary tumor was conserved in six recurrent tumors after interim chemotherapy. None of the 12 tumors with BRCA1 promoter hypermethylation demonstrated BRCA1 protein expression by immunohistochemistry. BRCA1 methylation was only seen in ovarian cancer patients without a family history suggestive of a breast/ ovarian cancer syndrome. Therefore, the 12 BRCA1 methylated tumors represented 15% (12 of 81) of the sporadic cancers analyzed in this study. Although the clinical significance of BRCA1 promoter hypermethylation is yet to be determined, promoter hypermethylation may be an alternative to mutation in causing the inactivation of the BRCA1 tumor suppressor gene in sporadic ovarian cancer.
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PMID:BRCA1 promoter region hypermethylation in ovarian carcinoma: a population-based study. 1103 65

A human tumor xenograft (L56Br-X1) was established from a breast cancer axillary lymph node metastasis of a 53-year-old woman with a BRCA1 germ-line nonsense mutation (1806C>T; Q563X), and a cell line (L56Br-C1) was subsequently derived from the xenograft. The xenograft carries only the mutant BRCA1 allele and expresses mutant BRCA1 mRNA but no BRCA1 protein as determined by immunoprecipitation or Western blotting. The primary tumor, lymph node metastasis, and xenograft were hypodiploid by DNA flow cytometry, whereas the cell line displayed an aneuploidy apparently developed via polyploidization. Cytogenetic analysis, spectral karyotyping, and comparative genomic hybridization of the cell line revealed a highly complex karyotype with numerous unbalanced translocations. The xenograft and cell line had retained a somatic TP53 missense mutation (S215I) originating from the primary tumors, as well as a lack of immunohistochemically detectable expression of steroid hormone receptors, epidermal growth factor receptor, human epidermal growth factor receptor 2 (HER-2), and keratin 8. Global gene expression analysis by cDNA microarrays supported a correlation between the expression profiles of the primary tumor, lymph node metastasis, xenograft, and cell line. We conclude that L56Br-X1 and L56Br-C1 are useful model systems for studies of the pathogenesis and new therapeutic modalities of BRCA1-induced human breast cancer.
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PMID:Characterization of a novel breast carcinoma xenograft and cell line derived from a BRCA1 germ-line mutation carrier. 1264 39

Although ovarian carcinomas with mutated BRCA1 or BRCA2 are sensitive to platinum compounds, such carcinomas eventually develop platinum resistance. Previously, we showed that acquired resistance to cisplatin in BRCA2-mutated tumors can be mediated by secondary intragenic mutations in BRCA2 that restore the wild-type BRCA2 reading frame. Here, we show that secondary mutations of BRCA1 also occur in BRCA1-mutated ovarian cancer with platinum resistance. We evaluated nine recurrent BRCA1-mutated ovarian cancers previously treated with platinum compounds, including five with acquired platinum resistance, one with primary platinum resistance, and three with platinum sensitivity. Four of the six recurrent platinum-resistant tumors had developed secondary genetic changes in BRCA1 that restored the reading frame of the BRCA1 protein, whereas none of the three platinum-sensitive recurrent tumors developed BRCA1 sequence alterations. We immunohistochemically confirmed restored expression of BRCA1 protein in two cases with secondary mutations. Intriguingly, the case with primary platinum resistance showed back mutation of BRCA1 in the primary tumor and showed another secondary mutation in the recurrent tumor. Our results suggest that secondary mutations in BRCA1 can mediate resistance to platinum in BRCA1-mutated ovarian tumors.
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PMID:Secondary BRCA1 mutations in BRCA1-mutated ovarian carcinomas with platinum resistance. 1841 25

Uterine serous carcinoma is a uncommon aggressive variant of endometrial cancer whose biologic origin is unclear. Mutations in p53 and BRCA1 genes play a key role in ovarian serous carcinogenesis. We investigated whether the loss of BRCA1 expression plays a similar role in uterine serous carcinoma. Loss of BRCA1 expression and Wilms tumor 1 (WT-1) overexpression were detected by immunohistochemical analysis. Depth of myometrial invasion, the presence of precursor lesions or polyps, and clinical parameters (age, history of breast cancer, and germline BRCA1 mutation status) were recorded. A total of 27 cases were available for evaluation. Three tumors (11.1%, 95% confidence interval, 2%-29%) showed the loss of BRCA1 expression. Two of these had known germline mutation in BRCA1, and the third had not been analyzed. Two of these cases expressed WT-1 or showed some morphologic features suggestive of drop metastasis from the adnexa, but no case showed detectable serous tubal intraepithelial carcinoma or features of an ovarian primary tumor. Overall, 5 women in the group had a personal history of breast cancer, and the finding was significantly associated with BRCA1 staining (P=0.049). A subset of uterine serous carcinomas shows the loss of BRCA1 protein and is associated with germline mutation.
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PMID:Immunohistochemical loss of BRCA1 protein in uterine serous carcinoma. 2468 40