Purpose of review: The highly heterogeneous clinical, histological, biological and genetic nature of breast malignancies is due in part to their extreme molecular complexity.
Recent findings: Many genetic and epigenetic alterations have been described, affecting a relatively small number of signaling pathways (PI3K, NK-κB, FGF, etc.) and thus several molecular subtypes of breast cancer have been identified.
Summary: The next decade will see even more prolific developments, notably with the advent of next-generation sequencing (NGS) technologies capable of providing individual patients' constitutional and somatic genome sequences both rapidly and cheaply. Knowledge of the full catalogue of somatic genetic alterations will pave the way for fully individualized management of breast cancer patients.