Biomarkers in Breast Cancer and the Implications of Their Discordance

The analysis of biomarkers in breast cancer has made a large impact in treatment decisions and determining prognosis. Information gained from the phenotypic and molecular profile helps both in prognostic stratification as well as treatment selection. With the advent of newer more efficacious chemotherapeutic and biological agents in the management of metastatic breast cancer, most women with this disease are exposed to multiple lines of therapy. Discordance in the receptor status between the primary and metastatic sites is frequently encountered and may play an important role in deciding subsequent therapy. In this review, we look at the role of current biomarkers in the management of breast cancer, which are promising and the therapeutic and prognostic implications of their discordance during the natural course of disease progression.