PTCH1 and skin basal cell carcinoma: To gain further insight into the neoplastic potential of skin nevi, we evaluated the expression of oncogenic markers characteristic of BCC (Ptch-1, Gli-1, and Gli-2) (18), SCC (K8, K17, and p63) (19–21), and melanoma (c-kit, MAGE, and CDK4) (22,23).