Histopathologic examination of skin tumors in our Ptch1+/−/SKH-1 animals revealed interfollicular basaloid cell proliferation in patterns virtually indistinguishable from human BCCs, and trichoblastomas typical of patients with NBCCS (Figure 1A, lower panel and Supplemental Figure S2B and S2C). This evidence concerns the gene PTCH1 and nevoid basal cell carcinoma syndrome.