Regulation of cancer stem cells by p53

The hypothesis that cancer stem cells are responsible for the chemoresistant and metastatic phenotypes of many breast cancers has gained support using cell-sorting strategies to enrich the tumor-initiating population of cells. The mechanisms regulating the cancer stem cell pool, however, are less clear. Two recent publications suggest that loss of p53 permits expansion of presumptive cancer stem cells in mouse mammary tumors and in human breast cell lines. These results add restriction of cancer stem cells as a new tumor suppressor activity attributed to p53.