IHH and neoplasm: Hh neutralizing antibodies, including 5E1 (152, 153), a Shh monoclonal antibody, and MEDI-5304 (154), a Shh and Ihh monoclonal antibody, and small molecule compounds, including Robotnikinin and HL2-m5 (155, 156), have been reported to disrupt Hh/PTCH interactions, thereby suppressing Hh pathway and exhibiting anti-tumor activity.