CD274 and bone sarcoma: Our results validated pervious evidences regarding the possible photogenic role of PD-L1 in bone tumors, however inclusion of assessing another regulator such as TGF- β and IFN-γ as well as investigating of other bone sarcomas with higher tumor diversity and malignancy allowed us to have more comprehensive picture of how PD-L1 may work in these tumors (Fig. 7).