New generation of molecular prognostic and predictive tests for breast cancer.

Breast cancer is a clinically heterogeneous disease, and it is generally accepted that the different clinical courses of patients with histologically similar tumors are due to molecular differences among cancers. Therefore, detailed molecular analysis of the cancer could yield prognostic information. Recent advances in molecular analytical techniques have led to rapid expansion of novel diagnostics designed to personalize breast cancer care. Diagnostic companies are also increasingly adopting a clinical trial-based approach to develop their products. This article reviews some of the most important advances in this field in the past few years, including the emergence of several multigene and prognostic predictors, as well as methods allowing enumeration of circulating tumor cells that are currently offered as commercially available diagnostic assays.