Review ArticlesTriple Negative Breast Carcinomas Similarities and Differences With Basal Like CarcinomasLerma, Enrique MD*; Barnadas, Agusti MD†; Prat, Jaime MD*Author Information *Department of Pathology †Department of Oncology, Hospital de la Santa Creu i Sant Pau, Autonomous University of Barcelona, Barcelona, Spain This study was supported in part by grants from Fondo de Investigaciones Sanitarias (FIS PI06- 0709), Instituto Carlos III RTICCCFIS RD06/0020/0015, Pfizer Laboratories, and Mutua Madrileña Foundation. The authors declare that they do not have any conflict of interest. Reprints: Jaime Prat, MD, Department of Pathology, Hospital de la Santa Creu i Sant Pau, Avenida Sant Antoni Maria Claret 167, 08025 Barcelona, Spain (e-mail: [email protected]). Received for publication March 6, 2009; accepted March 24, 2009 Applied Immunohistochemistry & Molecular Morphology: December 2009 - Volume 17 - Issue 6 - p 483-494 doi: 10.1097/PAI.0b013e3181a725eb Buy Metrics Abstract The cDNA microarrays allows the classification of breast cancers into 6 groups: luminal A, luminal B, luminal C, normal breast-like, human epidermal growth factor receptor 2-positive, and basal-like. This latter is characterized by the expression of basal cytokeratins (CKs), and frequent negativity for hormone receptors and human epidermal growth factor receptor 2. There is a marked parallelism between triple negative breast carcinomas and basal-like carcinoma, but these are not equivalent terms. Estimated concordance is around 80%. CK5 seems to be the best marker for the identification of these tumors. Other good markers to identify these tumors are CK14, CK17, and epidermal growth factor receptor. A subset of triple negative breast carcinomas has myoepithelial differentiation, with positivities for smooth muscle actin, p63, S-100, and CD10 among others. Recent studies suggest that basal like carcinomas are originated from mammary stem cells. © 2009 Lippincott Williams & Wilkins, Inc.