[New prognostic and predictive markers for breast cancer]

Breast cancer can be divided into four molecular subtypes with different prognoses using immunohistochemical markers in the routine clinicopathological work-up. The protein Ki-67 is of central importance in this context, in particular to distinguish between luminal A and luminal B carcinomas. Determination of the Ki-67 index of a carcinoma also allows a prediction of the likelihood of the response to chemotherapy. Additionally, the expression of certain cytokeratins in tumor cells is associated with a poor response to chemotherapy. The heterogeneity of molecular subtypes with regard to the histological appearance indicates an even greater diversity of breast cancer. We were able to show that a high proportion of luminal B carcinomas display neuroendocrine differentiation. Further studies with particular emphasis on histomorphological criteria should be performed to attain a more accurate classification of breast cancer and to pave the way towards targeted therapies for a better prognosis in the future.