Skin Cancer Starts When Tanning Goes Wrong in Mutated Stem Cells

The origin of melanoma, one of the deadliest cancers, precedes the usual warning signs—the appearance of new or changing skin lesions. Melanoma actually begins in individual cells, most often in cells located in clear skin. But exactly which cells, under what circumstances, has been unclear. But now, reports a group of scientists based at Cornell University, melanoma may arise from melanocyte stem cells (MCSCs), specifically, MCSCs that have become “melanoma competent” because