STAT3 and osteosarcoma: In addition, apatinib has been shown to inhibit osteosarcoma cell proliferation and induce osteosarcoma cell apoptosis and G0/G1 phase arrest in vitro, and inhibit cell invasion, migration and PD-1 expression, and the STAT3/ Bcl-2 signaling pathway is considered as a possible mechanism [21, 23].