MTOR and osteosarcoma: Downstream of AKT, instead, the activity of mTOR in osteosarcoma can be increased via deubiquitination by either OTU domain-containing 7B (OTUDB7), which increases mTORC2 activity by inhibiting TRAF2 [93,94], or by Ubiquitin-specific peptidase 9X (USP9X), able to enhance the signaling of both mTORC1 and 2 [95].