Researchers have unmasked a long sought stem cell origin of carcinoma and identified the genetic lesions occurring within these cells that spur them on to malignancy. The scientists have found that increased activity of a powerful oncogene called Ras combined with overly exuberant activity of a protein called ”Np63±, stimulates the population of skin stem cells that produce keratin 15 — one of many keratin proteins found in the skin — promoting carcinoma development.