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Query: UNIPROT:P04626 (erbB-2)
 5,251 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A method based on the reverse transcriptase-polymerase chain reaction (RT-PCR) was developed that allows the determination of relative mRNA expression levels in fine-needle aspirates from human tumors. The method was developed for the c-erbB-2 gene, using the porphobilinogen deaminase (PBGD) gene as an internal standard. It was validated for mRNA isolated from cell lines and for material obtained by fine-needle aspiration from human breast cancer. Gene expression levels were determined by measuring the activity of radiolabeled RT-PCR-amplified gene-specific bands with a phosphor imager. At least four points are measured on the log-linear part of the amplification cycle versus signal intensity curves, and subsequently the distance between the curves of the gene of interest and that of an internal standard gene is used to calculate the relative expression levels. The method worked equally well with the BRCA1 gene, illustrating that it can be generalized to other genes. The method is suitable to measure or monitor semiquantitively gene expression levels in accessible human tumors in situ.
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PMID:A method to monitor mRNA levels in human breast tumor cells obtained by fine-needle aspiration. 955 96

Hereditary ovarian cancers associated with germline mutations in either BRCA1 or BRCA2 were studied to determine whether somatic mutation of the P53 gene is required for BRCA-linked ovarian tumorigenesis and further, whether the spectrum of additional somatic molecular genetic alterations present in these tumors differs from that known to exist in sporadic ovarian cancers. Forty tumors, 29 linked to BRCA1 and 11 linked to BRCA2, were examined for mutational alterations in P53, K-RAS, ERBB-2, C-MYC, and AKT2. The presence of a P53 mutation in 80% of these cancers indicates that P53 mutation is common but not required for BRCA-linked ovarian tumorigenesis; notably, a significantly higher proportion of the P53 mutations in BRCA2-linked cancers were deletions or insertions compared with the more typical spectrum of missense mutations seen in BRCA1-linked cancers. Additionally, BRCA-linked ovarian carcinomas seem to develop through a unique pathway of tumorigenesis that does not involve mutation of K-RAS or amplification of ERBB-2, C-MYC, or AKT2.
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PMID:Molecular genetic characterization of BRCA1- and BRCA2-linked hereditary ovarian cancers. 969 40

Breast cancers arising in women with and without a germline mutation in the BRCA1 or BRCA2 gene display different histological features, which suggests unique mechanisms of molecular pathogenesis: We used a molecular pathological analysis to define the genetic abnormalities relevant to these specific pathogeneses. Tumor material was studied from 40 women with breast cancer diagnosed before 40 years of age, sampled from a population-based study and stratified by BRCA1 and BRCA2 germline mutation status. Cases were not selected for family history or ethnic origin, and none were known to be genetically related. Thus, germline mutation itself is likely to impact on the molecular pathogenesis of these tumors, with no substantial influence due to modifying genetic or environmental factors. Breast cancers occurring in BRCA1 mutation carriers had significantly higher levels of p53 expression, including the preinvasive (carcinoma in situ) stage of disease, compared with cancers occurring in BRCA2 mutation carriers or women with no detectable germline mutation. These cancers also had a higher proliferation rate as measured by Ki-67 antibody. Expression of the prognostic factors c-erbB-2, cyclin D1, and estrogen receptor was significantly less common in BRCA1 mutation carriers. Lower levels of cyclin D1 were also found in cancers from BRCA2 mutation carriers compared with non-mutation carriers. Direct p53 mutation analysis revealed mutations in 18% of all of the early-onset breast cancers within the study and included rare insertion and deletional mutations in cancers from BRCA1 mutation carriers. Our data indicate that a BRCA1 breast cancer phenotype may be recognized by an exceptionally high proliferation rate and early and frequent p53 overexpression but infrequent selection for overexpression of several other prognostic factor proteins known to be involved in breast oncogenesis. In contrast, breast cancers arising in BRCA2 mutation carriers have a more heterogeneous phenotypic profile.
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PMID:Distinct molecular pathogeneses of early-onset breast cancers in BRCA1 and BRCA2 mutation carriers: a population-based study. 1021 14

BRCA1 is a tumor suppressor gene that is responsible for hereditary breast and ovarian cancer syndrome. To clarify the possible involvement of the BRCA1 protein in mammary carcinogenesis in sporadic and hereditary forms, we have analyzed the BRCA1 protein expression pattern in five breast epithelial cell lines, including a BRCA1-deficient cell line, and 162 breast cancer tissue samples [including 108 sporadic, 35 hereditary (BRCA1 status unknown), and 19 BRCA1-associated cases] from Japanese women. Twelve anti-BRCA1 antibodies were tested by fixation conditions, in which nuclear localization of BRCA1 protein was preserved, and by specificity of the antibodies, which was evaluated in BRCA1-deficient cancer cells. Using monoclonal antibodies applicable to immunohistochemical analysis of paraffin-embedded tissue sections, we found high-level expression of BRCA1 protein in normal mammary epithelium and various degrees of reduced expression in breast cancer cells. Of the 19 BRCA1-associated breast cancer tissues, 15 (79%) showed reduction (8 cases) or complete loss (7 cases) of nuclear expression. Thirty (28%) of 108 sporadic and 6 (17%) of 35 hereditary carcinomas showed reduced BRCA1 protein expression. Reduction of BRCA1 protein expression in sporadic carcinomas was associated with solid-tubular phenotype, with poor tubular differentiation, and with an overexpression of c-erbB-2 protein, which is one of the prognostic factors in breast cancer. Our data suggest that reduced expression of BRCA1 protein may play an important role in mammary carcinogenesis, not only in BRCA1-associated breast carcinomas, but also in sporadic carcinomas, and also suggest that mechanisms other than mutation may be involved in its reduced expression.
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PMID:Reduction of BRCA1 protein expression in Japanese sporadic breast carcinomas and its frequent loss in BRCA1-associated cases. 1038 7

Breast cancer remains the leading cause of death in American women 30 to 70 years of age, and research in the field of breast cancer continues at an explosive pace. Our understanding of the molecular basis of familial breast cancer has advanced significantly through investigation of the tumor suppressor gene BRCA1, as has our knowledge of the role of the ATM gene and predisposition to breast cancer in ataxia-telangiectasia carriers. In addition, progress has been made in understanding the role of HER-2/neu as a prognostic factor in breast cancer. In this review, some of the recent advances in breast cancer biology that are relevant to these areas of study are highlighted.
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PMID:Recent advances in breast cancer biology. 1055 5

Ovarian cancer remains the leading cause of death from gynecologic malignancy in Western countries. This cancer results from a succession of genetic alterations involving oncogenes and tumor suppressor genes which have a critical role in normal cell growth regulation. Mutations and/or overexpression of three oncogenes, HER-2/neu, c-myc and K-ras, and of the tumor suppressor gene p53, have frequently been observed in sporadic ovarian cancer. In the context of high risk families, the most frequently involved genes are BRCA1 and BRCA2. We review the function of these different proteins, the incidence of mutations in their genes in carcinogenesis and as potential prognostic factors in sporadic and hereditary ovarian cancer.
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PMID:Major oncogenes and tumor suppressor genes involved in epithelial ovarian cancer (review). 1067 91

Hereditary non-polyposis colorectal cancer (HNPCC) is an autosomal dominant disease, predisposing to the development of colorectal cancer and other tumor types such as endometrial, small bowel, stomach, ovary and urinary tract carcinoma, while most investigators find no association between HNPCC and cancer of the breast. We have identified hMLH1 mutations in 2 Amsterdam-criteria HNPCC families where both male and female gene carriers were affected with breast cancer. To investigate whether these breast cancers were caused by other genetic factors, we analyzed the 2 breast cancer susceptibility genes BRCA1 and BRCA2. In one family we did not find any mutation in the breast cancer genes, while in the other, a BRCA1 mutation segregated in the breast cancer cases. Hereditary breast cancer, and in particular BRCA1 tumors, display discrete histo-pathological and immunohistological characteristics. The tumor from a woman with both hMLH1 mutations and a BRCA1 mutation exhibited typical BRCA1 histology, e.g., grade 3 invasive ductal carcinoma with dense lymphocytic infiltration, and immunohistology, estrogen receptor (ER) negative, progesterone receptor (PgR) negative, strongly p53 positive, c-erbB-2 negative and highly Ki67 positive (>50% stained cells). The histology of the breast tumor from the man with both one hMLH1 mutation and a BRCA1 mutation was a grade 2 invasive ductal carcinoma without any special BRCA1 features. Immunohistology was also different. This might merely reflect a true difference in male breast tumor progression vs. female. We cannot exclude that the combined effect of BRCA1 and hMLH1 dysfunction has a bearing on tumor progression.
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PMID:Germline BRCA1 and HMLH1 mutations in a family with male and female breast carcinoma. 1070 98

Papillary serous carcinoma of the peritoneum (PSCP) is believed to develop de novo from the peritoneal lining of the pelvis and abdomen. Although it is histologically indistinguishable from serous ovarian carcinoma, PSCP exhibits minimal or absent ovarian involvement and may even develop in a woman years after prophylactic oophorectomy. We have shown previously that patients with germ-line BRCA1 mutations who develop PSCP are more likely to have disease originating from multiple peritoneal sites compared with patients with wild-type BRCA1. In this study, we tested the hypothesis that BRCA1-related PSCP has a unique molecular pathogenesis. DNA was extracted from normal tissue and multiple tumor sites in patients with PSCP. BRCA1 and p53 gene mutations were screened for using single-strand conformation polymorphism. Loss of heterozygosity was determined at the BRCA1 and p53 loci. Immunohistochemical analyses of p53, epidermal growth factor receptor, erbB-2, erbB-3, erbB-4, and Bcl-2 expression were performed. We detected germ-line BRCA1 mutations in 11 (26%) of 43 PSCP patients. BRCA1 mutation carriers had a higher overall incidence of p53 mutations (89% versus 47%; P = 0.052), were more likely to exhibit multifocal or null p53 mutations (63% versus 7%; P = 0.014), and were less likely to exhibit erbB-2 overexpression (P = 0.013) than wild-type BRCA1 case subjects. We propose that the unique molecular pathogenesis of BRCA1-related PSCP may affect the ability of current methods to reliably prevent or detect this disease prior to metastasis.
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PMID:BRCA1-related papillary serous carcinoma of the peritoneum has a unique molecular pathogenesis. 1072 99

We examined a 34-year-old premenopausal woman who had noticed a left-breast lump a month previously. She had no past history of malignancies but had a family history of breast and ovarian cancers. Her mother had suffered from ovarian cancer when aged 47 years and had died of the disease at age 52. The younger two of the patient's four aunts had developed breast cancer when they were 37 and 48 years old. A physical examination showed an ill-defined mass, 1.5 cm in diameter, located in the upper outer quadrant of the patient's left breast. Mammography revealed diffuse microcalcification in both breasts but ultrasonography revealed an irregular tumorous lesion only in the left breast. Aspiration breast cytology revealed adenocarcinoma of the left breast. Modified radical mastectomy of the left breast and excision of a biopsy specimen from the right breast were carried out simultaneously. Histopathologically the left-breast tumor was an atypical medullary carcinoma with cartilaginous metaplasia, of histological grade 3, and the right-breast specimen showed fibrocystic changes with atypical ductal hyperplasia. Estrogen receptors were positive, but progesterone receptor was not detected on the tumor cells, which were immunopositive for nuclear p53 although c-erbB-2 overexpression was not observed. A nonsense germline mutation of the BRCA1 gene (exon5) was detected. The patient has been well since the operation (10 months). These findings may provide useful information about the carcinogenesis and biological behavior of BRCA1-associated breast cancers.
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PMID:Atypical medullary carcinoma of the breast with cartilaginous metaplasia in a patient with a BRCA1 germline mutation. 1077 May 66

Twelve well-differentiated villoglandular adenocarcinomas (WDVAs) of the uterine cervix were retrospectively analyzed for the presence and specific genotype of human papillomavirus (HPV), tumor suppressor loss (p53, MCC, APC, BRCA1), cancer gene mutation (K-ras-2, exons 1 and 2, p53 exons 5 to 8), and oncogene amplification (c-erbB-2/HER-2/neu, int-2). Tissue for genetic evaluation was obtained by microdissection, using 4-micron-thick histology sections of archival, formalin-fixed, paraffin-embedded specimens. Genotyping involved nucleic acid amplification and DNA sequencing with gene-specific oligonucleotides and L1 region consensus primers for common strains of HPV. Point mutation and HPV strain determination were accomplished by DNA sequence analysis. Tumor suppressor gene loss and oncogene amplification were performed by allelic imbalance analysis in informative subjects based on DNA sequence and microsatellite-length polymorphisms. HPV was present in all tumors and consisted of type 16 (n = 5, 42%) and type 18 (n = 7, 58%) strains, which have been closely associated with cervical neoplasia. K-ras-2 and p53 genes did not manifest point mutational damage. There was no evidence of oncogene amplification or tumor suppressor gene loss. The presence of HPV in all 12 tumors supports the role of HPV infection in the molecular pathogenesis of this uncommon neoplasm. The absence of associated oncogene or tumor suppressor gene damage is consistent with indolent biological behavior and the favorable prognosis of this unusual tumor.
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PMID:Well-differentiated villoglandular adenocarcinoma of the uterine cervix: oncogene/tumor suppressor gene alterations and human papillomavirus genotyping. 1078 6


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