IGF1 and osteosarcoma: It is well known that IGF-1 plays important roles in cell proliferation, motility, and metastasis.26,27 Amplified IGF-1/IGF-1R signaling is not only associated with development of tumors, but also contributes to tumor cell survival, invasion, metastasis, and resistance to chemotherapeutic drugs.27,28 In our studies, we confirmed that IGF-1 was a direct target of miR-26a in osteosarcoma cells.