SMO and osteosarcoma: Of note, several hedgehog-signaling components, including smoothened (SMO), GLI family zinc finger proteins 1 and 2 (GLI1 and GLI2) and patched 1 (PTCH1), were found overexpressed in human osteosarcoma, and knockdown of GLI2 recapitulated the YAP knockdown effect in suppressing the proliferation, invasion and EMT of osteosarcoma cell lines [189,190].