The skin of K14-Shh transgenic mice is characterized by multiple BCC-like proliferations, associated with two distinct cellular phenotypes within the epidermis, which range from marked progenitor-cell hyperplasia and wrinkled, blistered skin through to a complete loss of tissue renewal within the epidermis and taut, shiny, translucent skin. The gene discussed is SHH; the disease is skin basal cell carcinoma.