Breast cancer: origins and evolution

Breast cancer is not a single disease, but rather is composed of distinct subtypes assosiated with different clinical outcomes. understanding this heterogeneity is key for the development of targeted cancer-preventative and -therapeutic interventions. Current models explaining inter- and intr- tumoral diversity are the cancer stem cell and the clonal evolution hypothesis. Although tumor initiation and progression are predominantly driven by acquired genetic alterations, recent data implicate a role for microenvironmental and epigenetic changes as well. Comprehensive unbiased studies of tumors and patient populations have significantly advanced our molecular understanding of breast cancer, but translating these findings into clinical practice remains a challenge.