CTLA4 and neoplasm: In a series of 29 cases of chondrosarcoma and liposarcoma, PD-L1 on tumor cells was found to be present in 100% of cases, but only 11% and 45% were found to have PD-1 positive infiltrating T-cells [8]. Increased CTLA-4 T-cells were found in aggressive pediatric sarcoma patients and the mutagenic burden of tumors has been correlated with the strength of tumor-specific immune response with checkpoint inhibitor therapy [9].