FAS and cancer: While PD-1 reduces glycolytic metabolism and FAS, PD-L1 expression in cancer cells promotes glycolysis via an Akt/mTOR/HIF-1α axis, while in the case of cancer harboring RAS family mutation (the mutation frequency of the Ras family in cancer is common and reaches approximately 19% [173]), the axis may be further tuned on since it was reported that RAS signaling could stabilize the expression of PD-L1 [174].