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Background: Male breast cancer is suggested to be biologically different from female breast cancer. The differences in clinicopathology between male and female breast cancer raise the issues of establishing specific strategies and treatment regime for male breast cancer patients. The single most significant risk factor for male breast cancer is a mutation in the BRCA2 gene. The lack of information on hereditary breast cancer in male, particularly in Asians, leaves great but forgiven research area on epidemiological studies for this group of patients. Methods: All male breast cancer patients and their family members, from a Hong Kong Hereditary and High Risk Breast Cancer Program since year 2007, were recruited in this study. All received genetic counseling and BRCA mutation testing using DNA extracted from blood samples. A questionnaire was administered at their first visit which included questions on their demographics and socioeconomic status. Other information including family history of breast cancer or other kinds of cancer, method of diagnosis, surgical strategies, pathological results, treatment regime, relapse, metastasis, and outcomes were obtained from their medical records. Descriptive analysis was performed describing the background characteristics. Chi-square test and Student's t-test were applied to calculate the associations between BRCA mutation and risk factors. Survival analysis was performed to look for their survival patterns. Results: Thirty-six male breast cancer patients were recruited between year 2007 and 2012, while 21 were diagnosed before year 2007 (range: 1996 to 2012). Mean, standard deviation, and median follow-up time were 5.75±4.31 and 5.25 years. Seven were found to carry the BRCA mutation. All were BRCA2 mutation and the mutation rate was 19.4% (N = 7). Family history of cancer was found in 52.8% (N = 19). Male BRCA mutation carriers were found to have higher risk of secondary cancer, and their first and second degree family members had higher risk of either breast cancer or other kinds of cancers. T stage in BRCA patients was significantly higher than non-BRCA patients (p = 0.028). All BRCA mutation carriers had ER positive cancers compared with 96.2% who were non-carriers. Half of the male BRCA patients were PR positive compared with higher percentage in non-BRCA patients (50% vs. 80.8%, p = 0.117). Both groups had similar overall (p = 0.962) and disease-free survivals (p = 0.919). The means and standard deviations of 5-year overall survival between BRCA and non-BRCA patients were 2.08±0.25 and 4.24±0.12 years respectively, and 2.08±3.03 and 4.41±1.46 years for disease-free survival. Conclusions: The prevalence of male breast cancer patients with BRCA2 mutation in Hong Kong is comparable with other similar studies. Male breast cancer patients with BRCA2 mutation are suspected to have higher chance of secondary cancer and familial cancer. Although percentage of ER positive cancers are similar to the two groups, BRCA2 mutation carriers tend to have less PR positive cancers which may suggest a poorer prognosis although due to a small sample size this cannot be shown in this cohort. Further collaborative studies to better understand male breast cancer patients carrying the BRCA mutation is warranted. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-11-02.

Background and Aims: Germline mutations in the two breast cancer susceptibility genes, BRCA1 and BRCA2 account for a significant portion of hereditary breast/ovarian cancer. Most of the BRCA mutations reported in Southern Chinese patients were point mutations, small deletions, and insertions. The spectrum of large genomic rearrangement (LGR) is largely unknown. Here we perform the first study on the LGR of BRCA genes in a Hong Kong Chinese population. We aimed to determine the spectrum of BRCA LGRs in Southern Chinese patients with breast cancer. Methods: A total of 555 clinically high-risk breast and/or ovarian cancer patients were recruited from the Hong Kong Hereditary Breast Cancer Family Registry, diagnosed from March 2007 to November 2011. Multiplex ligation-dependent probe amplification (MLPA) for detecting BRCA LGRs together with comprehensive BRCA1 and BRCA2 gene sequencing of all coding exons were performed. cDNA sequencing of the LGRs was performed to locate the breakpoint of the deletions. Results: Overall BRCA1/2 mutation prevalence among this cohort was 12.4% (69/555). Among the 69 mutations identified, 4 novel LGRs (2 in BRCA1 and 2 in BRCA2) were detected only by MLPA but not full gene sequencing. Overall the LGR genes accounted for 5.8% (4/69) of all BRCA mutations in our cohort, 6.9% (2/29) of all BRCA1 mutations and 5% (2/40) of all BRCA2 mutations. Conclusions: These findings highlight the LGR spectrum of BRCA1 and BRCA2 genes in Southern Chinese breast cancer patients. LGR testing together with BRCA1/2 full gene sequencing is superior to other methods for comprehensive BRCA1/2 analysis in clinical settings. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-11-02.

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