MTOR and osteosarcoma: Furthermore, common cancer-associated pathways such as the phosphatidylinositol 3-kinase/mammalian target of rapamycin (PI3K/mTOR) pathway and insulin-like growth factor (IGF) signaling have also been found to be abnormal in osteosarcoma (Perry et al., 2014; Behjati et al., 2017).