CD8A and neoplasm: Meanwhile, tumor cells disrupt CD8+ T-cell methionine metabolism through high expression of the transporter SLC43A2 to consume large amounts of methionine in the TME, which reduces methionine and SAM levels, leading to loss of histone H3 (H3K79me2) dimethylation, low STAT5 expression, and impaired T-cell immunity [352].