Beneficial anti-cancer effects of systemic in vivo cyclopamine treatment in mice. Ptch1+/-;p53-/- mice develop medulloblastoma and die at 2 months of age. Treatment with cyclopamine through systemic intraperitoneal injections for 30 days starting at 1 month of age results in a great diminution of tumor size, seen from a dorsal view of the whole dissected brain (A,D) and lack of significant tumor-associated behavior anomalies. Hemisections of the brain and histological preparations show massive tumors in Ptch1+/-;p53-/- mice treated with carrier alone (cyclodextrin, B,C), but much reduced tumors in cyclopamine-treated siblings (E,F). A,B,D,E) show unstained tissue. C,F) show cerebellar sections after X-Gal histochemistry. Arrows point to tumors. After reference 162.