Basal phenotype in breast carcinoma occurring in women aged 35 or younger.

Breast cancer in the young is considered a special clinical presentation of the disease. Sixty-nine breast cancer cases diagnosed at or before the age of 35 were analyzed for common morphological and immunophenotypical features of basal-like carcinomas. Sixteen carcinomas displayed the immunophenotypical characteristics (estrogen receptor and HER2 negativity and positivity for at least one of the following basal markers: cytokeratin 5 or 14, epidermal growth factor receptor, p63) of basal-like carcinomas, and most of them demonstrated characteristic histological features (pushing borders, lymphocytic peritumoral infiltrate, central hypocellular zone or necrosis, high mitotic rate) too. These tumors were more likely to be high-molecular-weight cytokeratin: 34betaE12 and p53 positive by immunohistochemistry. The presence of a basal-like phenotype can be important as concerns systemic treatment issues and could theoretically be associated with a higher rate of BRCA1 mutations in the young, because of the overlap of BRCA1 mutation associated breast carcinomas and the basal-like phenotype.