MW is a consultant for and has financial holdings in OncoMed Pharmaceuticals.
The epithelial components of the mammary gland are thought to arise from a stem cell capable of both self-renewal and multi-lineage differentiation. Furthermore, there is increasing evidence that mammary carcinomas originate in these cells or their immediate progeny. The recent identification of murine mammary stem cells should facilitate their molecular characterization and help to elucidate their role in mammary carcinogenesis. In addition, an understanding of the biology of these cells including the pathways that regulate their self-renewal and differentiation may suggest new approaches for the prevention and treatment of breast cancer.