Decreased intracellular methionine levels, along with decreased availability of the methyl donor (SAM), result in reduced dimethylation of histone H3 at lysine 79 (H3K79me2), which suppresses STAT5 expression and impairs T-cell immunity.220 Oral formate augments the fitness of CD8 + T cells within the TME, promotes tumor clearance221 and promotes the survival of Foxp3+ Treg cells,222 which function in intestinal immunity. This evidence concerns the gene CD8A and neoplasm.