Immunohistochemical Markers for Distinguishing Metastatic Breast Carcinoma from Other Common Malignancies: Update and Revisit

Due to the high prevalence of breast cancer in the female, a metastasis from primary breast cancer is usually considered in the differential diagnosis of metastatic carcinoma in the female patient, even for those without a history of breast cancer, as some breast cancers are first diagnosed as metastases. Immunohistochemical analysis for breast cancer markers is the most common way to determine breast cancer origin besides clinical history and histology. In this review, we (1) summarize the commonly used and the newly identified breast cancer markers, including GCDFP-15, mammaglobin, GATA3, SOX10, and TRPS1; (2) point out the strengths and weaknesses of using these markers for breast cancers with luminal/epithelial or basal/myoepithelial differentiation; and (3) recommend diagnostic panels to differentiate breast carcinoma from carcinoma with similar morphology of other origins.