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.