Home > Cancer > What is Breast Cancer Get the Flash Player to see this player. Rate: (Click the stars to rate) Published on Oct 04, 2008 by MOsborne, Views: 4922 Breast cancer is the most common cancer in women. It is an abnormal growth of cells in the breast that can invade the breast tissue and spread to lymph nodes and metastasize. Risk factors are complex, including a strong family history, carrying a BRCA gene mutation, BRCA1 or BRCA2, as well as nutrtitional factors, such as a western diet. Most cases are spontaneous.