PTEN and skin neoplasm: To further examine the contribution of Lgr5+ HFSCs with Pten loss and their progeny to skin tumor development, we used Lgr5-CreER; Ptenflox/flox; Rosa-mTmG (Lgr5-Pten-/--mTmG) and Lgr5-CreER;Rosa-mTmG (Lgr5-mTmG) mice (control).