BRCA1 and BRCA2 mutation status and tumor characteristics in male breast cancer: a population-based study in Italy.

To investigate at the population level the impact of BRCA1/BRCA2 gene alterations in male breast cancer, we analyzed a population-based series of 25 male breast cancer cases from Florence, Central Italy. We combined mutational screening with the study of germ-line allele transcript levels and of tumor-associated losses of heterozygosity. Screening by protein truncation test and single-strand conformational polymorphism assay, followed by sequencing, revealed 4 pathogenetic mutations (4 of 25 = 16%; 95% confidence interval, 5-37%), 1 in BRCA1 and 3 in BRCA2, including mutations recurring in Central Italy (BRCA1 3345delAG and BRCA2 6696delTC). The a priori probability of carrying a mutation, estimated using BRCAPRO software, showed a good agreement between expected and observed mutations (14% versus 16%). A 7-fold association between germ-line mutations and family history of breast-ovarian cancer emerged. To investigate associations between BRCA1/BRCA2 status and clinicopathological characteristics, we analyzed the histopathological and immunophenotypic parameters of the tumors. A significant association emerged between mutation carrier status and high histological grade (P = 0.02). Furthermore, one BRCA2 carrier was affected with Paget's disease, an extremely rare male breast cancer histotype. Overall, BRCA1/2 mutations were observed to be strongly associated with positive c-erbB-2 immunostaining (P = 0.004). To evaluate germ-line allele expression, we used primer extension assays targeting frequent BRCA1 and BRCA2 polymorphisms. A BRCA2 allele transcript imbalance was found in one of four heterozygotes tested, all of them negative for germ-line mutations. BRCA1 transcript imbalances were not detected in nine heterozygotes analyzed. Losses of heterozygosity at one or more of nine loci in the BRCA2 region were found in 8 of 22 tumors tested. Interestingly, a case that was negative for BRCA1/BRCA2 germ-line mutations and that had a priori mutation probability <10% showed loss of heterozygosity at all three of the intragenic BRCA2 markers analyzed, which could be related to a somatic involvement of BRCA2. No losses of heterozygosity were detected at BRCA1. In conclusion, constitutional BRCA1/BRCA2 mutations accounted for 16% of the male breast cancer cases in this area of Central Italy. The detection of a BRCA2 germ-line transcript imbalance and of a somatic loss of BRCA2 among the cases that resulted negative for germ-line mutations suggests a role of this gene more relevant than indicated by conventional mutational analysis. A distinct pattern of characteristics indicative of aggressive behavior, including high-grade and c-erbB-2 expression, was evident in tumors from germ-line BRCA2 mutation carriers. This suggests that phenotypic characteristics may contribute to the identification of hereditary BRCA2-related male breast cancers and that these tumors might share a unique molecular pathway of cancer progression.

Does family history influence survival in breast cancer cases?

A few studies have suggested a relatively better prognosis for breast cancer (BC) cases reporting a positive family history (FH). We aimed at comparing the survival of patients according to FH in a large hospital-based series of 1,278 BC cases. Information on FH for BC was obtained at diagnosis by interview. All cases reporting a first- or second-degree FH for breast carcinoma were compared with cases without FH. Overall survival was estimated using a product-limit method. Hazard ratios (HRs) and the corresponding 95% confidence intervals (95% CIs), adjusted for confounding factors, were computed using proportional hazard models. Overall, 240 (18.8%) cases reporting, at diagnosis, a positive FH (156 with at least 1 first-degree relative and 84 with at least 1 second-degree relative) were compared with 1,038 patients without FH for BC. No significant differences were found in terms of distribution of age at diagnosis, tumor stage, nodal involvement, receptor status and histology. Cumulative survival rates at 5 years for cases without FH and with first-degree and second-degree FH for BC were 79.8 (95% CI 77.0-83.0), 78.6 (95% CI 70.0-88.0) and 80.2 (95% CI 68.0-92.0), respectively (log-rank test, chi(2) (2) = 0.02, p = 1.0). After adjustment for age, pathologic size and nodal involvement, the HR among cases of invasive cancer with a first-degree FH of BC was 0.91 (95% CI 0.55-1.48); however, the HR for cases with second-degree FH was 1.18 (95% CI 0.62-2.25) compared to cases without FH. Our study, based on a large series of consecutive invasive BC cases, did not find any significant survival differences associated with a positive FH for breast carcinoma, suggesting the existence of a large heterogeneity among BC cases with FH.