MUTATIONS OF THE P53 GENE IN MALE BREAST-CANCER

Background. Cancer of the male breast (MBC) is rare, accounting for less than 1% of cancer in males and representing less than 1% of all breast cancers. Reports of abnormalities in the expression of the tumor suppressor gene p53 in MBC have been few. Methods. To assess the expression and mutations of the p53 gene, 35 patients with 36 MBC (one patient with bilateral breast carcinoma) were examined using immunohistochemical methods, polymerase chain reaction (PCR)-single strand conformation polymorphism and DNA sequencing. Results. Thirty-one of the 36 carcinomas were studied by immunohistochemistry and by the PCR-based approach. Five patients were studied by immunohistochemistry only. Twelve patients (41.4%) of the 29 studied by molecular analysis presented an altered pattern in the single strand conformation polymorphism gel and point mutations were confirmed in all by direct DNA sequencing. Thirty-six tumors were studied by immunohistochemistry and 2 (5.5%) patients showed overexpression of the p53 protein. There were no statistically significant differences in p53 status with respect to: age, stage, estrogen receptors, progesterone receptors, tumor type. Patients with normal p53 showed a predisposition, although not statistically significant, for a longer disease free survival (5.6 years versus 4.2 years) and overall survival (5.9 years versus 4.8 years) than did patients with genetically altered p53. Conclusions. The incidence of male patients detected with p53 mutations (41.4%) in this series is concordant with the incidence of p53 mutations in female breast cancer, supporting the idea that cancer of the male breast is similar to the female counterpart.