Stem cells of the breast and cancer therapy

Breast cancer remains a significant public health problem despite advances in the understanding of the molecular and cellular events that underlie the disease. Crucial pathways regulating the cell cycle, proliferation and survival of breast cancer cells have been investigated and aberrant components of these pathways have been exploited as new drug targets. However, the mortality from breast cancer is only slowly declining. Recently, a model has been proposed that might explain the heterogeneous biological features of breast cancer cell populations and their differential response to therapeutic agents, which has interesting implications for further progress in therapy. This model links the emergence of breast cancer cells to stem cells and progenitors, an observation originally made in other cancer entities. It hypothesizes that the tumors originate from a small population of undifferentiated cells. These cells can undergo self-renewal and are able to generate a large number of partially differentiated ce...