In the PNAS Early Edition this week, Sunny Wong and Jeremy Reiter show that wounding recruits stem cells from the hair-follicle bulge and secondary hair germ to the injury site and that the downstream Hedgehog "signal transduction is de-repressed, giving rise to superficial BCC [basal cell carcinoma]-like tumors," which serves to explain, in part, the documented relationship between wounding and tumorigenesis.