Cyclopamine is an inhibitor of hedgehog (Hh) signaling, likely via direct inhibition of Smoothened, the accessory protein to the putative Hh receptor Patched. Cyclopamine is a teratogen isolated from the corn lily that causes usually fatal birth defects. It can prevent the fetal brain from dividing into two lobes (holoprosencephaly) and cause the development of a single eye. Cyclopamine can also be used to induce differentiation of human embryonic stem cells (hESCs) into hormone-expressing endocrine cells. In the very first at any time human affected person with metastatic pancreatic most cancers who was administered intravenous cyclopamine on a compassionate, experimental basis in Germany, cyclopamine had to be discontinued because of emergence of neurologic toxicities and hematologic toxicities. That may possibly severely impede or even prevent scientific trials with this promising therapeutic technique.