PTCH2 and skin basal cell carcinoma: Germline inactivation of one copy of the Hh receptor Patched 1 (PTCH1) gene [36] and, more rarely, of PTCH2 [37], or of Suppressor of Fused (SUFU) [38], followed by the somatic loss of the second allele results in Gorlin syndrome [12] that are frequently observed in BCC patients.