IFNG and neoplasm: Lactate acidosis restricts the cytolytic functions of natural killer (NK) cells by inhibition of nuclear factor of activated T cells (NFAT), reducing IFNγ production and downregulation of peroxisome proliferator-activated receptor g (PPARg) (66).Tumor derived lactate has also been shown to inhibit cytotoxic NK cell activity by inhibiting the production of perforin and granzyme or indirectly by enhancing the numbers of myeloid derived suppressor cells that suppress the functionality of NK cells (67).