SOX2 and osteosarcoma: Further studies showed that knockout of Sox2 inhibits glioblastoma cell proliferation and tumorigenicity, which suggests that Sox2 is the basis for maintaining the self-renewal ability of tumor-initiating cells (TICs).83 Sox2 also maintains the self-renewal of TICs in osteosarcomas, and downregulation of Sox2 drastically decreases its transformative characteristics and tumorigenesis ability in vitro.