The majority of triple-negative breast cancer may correspond to basal-like carcinoma, but triple-negative breast cancer is not identical to basal-like carcinoma.

Recently, the concept of basal-like carcinoma has been proposed. However, there are only a few reports about the relationship between triple-negative cancer and basal-like carcinoma. In this article, we report the study of the expression of basal cell markers in 11 triple-negative cancers. Eight tumors (4 metaplastic carcinomas, 2 invasive ductal carcinomas, 1 invasive papillary carcinoma, and 1 medullary carcinoma) were positive for more than three markers among cytokeratins 5, 14, and 17, and p63. Three tumors (2 invasive ductal carcinomas and 1 apocrine carcinoma) were completely negative for all markers. Among 8 tumors positive for basal markers, cytokeratins 5 and 17 were expressed in all 8 tumors, cytokeratin 14 in 6 tumors, and p63 in 7 tumors. Finally, we conclude that the majority of triple-negative cancer may correspond to basal-like carcinoma, but the two entities are not identical. The use of combination immunohistochemistry including cytokeratins 5, 14, and 17 and p63 may contribute to the detection of basal-like carcinoma.