Harnessing TGF-β and BMP signaling for expansion of p63-positive epithelial stem cells

p63-expressing stem cells characterize many epithelial cell-lined structures including the epidermis, thymus, mammary gland, lung and prostate. Within these compartments, the p63-postive (p63+) cells proliferate and differentiate to generate a p63-negative population of specialized epithelial cells, while maintaining a basal population of stem cells (1). Research in regional stem cells of epithelial cell origin in human disease, such as breast cancer and genetic lung diseases, has been intensified by recent therapeutic successes and the possibility to personalize therapy by testing individual tissue samples. In a recent report, Mou et al. describe a facile method using inhibitors of TGF-β and BMP signaling to expand p63+ cells from multiple different tissues, with the capacity to induce in vitro proliferation of even single cells, thus providing a new tool to potentially speed the discovery of new treatments (2).