Constitutive activation of the HH pathway has been observed in various types of malignancies caused either by mutations in the pathway, such as PTCH1 loss-of function or SMO activation in basal cell carcinoma, or through HH overexpression, as observed in small-cell lung cancer, glioma, endometrial carcinoma, digestive tract tumors, pancreas, and prostate [10,11,12,13,14,15,16]. The gene discussed is PTCH1; the disease is basal cell carcinoma.