Molecular diagnosis in breast cancer

Breast cancer is a complex and heterogeneous disease, encompassing a plethora of different entities with distinct biological features and clinical behaviour. The advent of high throughput molecular methods has allowed a systematic characterization of the molecular subtypes of breast cancer, the identification of novel therapeutic targets, and prognostic/predictive ‘gene signatures’. These methods are having a profound effect on the understanding of breast cancer, but their use in clinical practice is still rather limited.In this review, we discuss the main contribution of molecular methods for breast cancer research and how this information is changing the diagnosis and management of breast cancer. We also address novel developments in the diagnosis and management of HER2-positive breast carcinomas and familial breast cancer.