PTCH1 and skin basal cell carcinoma: To investigate the role of Il1 and Osm in BIT induction in vivo, we generated allograft secondary BCC tumors in Nod-Scid mice using primary mouse BCC tumors from our X-ray irradiated Ptch1+/−;p53f/f;K14Cre-ER;RFPf-s-f mouse model, followed by intra-tumoral injections of PBS control or Il1a + Osm ligand cocktail at 3-day interval for 18 days (Fig. 7a).