PTCH1 and skin basal cell carcinoma: We analyzed a panel of 13 BCC marker genes previously identified in an Italian study [24], including PTCH1, SMO, GLI1, CSMD1, CSMD2, NOTCH1, NOTCH2, TP53, ITIH2, DPP10, and STEAP4, as well as promoter mutations in TERT and DPH3.