CD274 and breast cancer: In BC, higher m6A modification levels are associated with elevated expression of HLA-A and more tumor-infiltrating CD8+ T cells, helper T cells, and natural killer cells, but decreased expression of programmed cell death protein ligand 1 (PD-L1), PD-L2, T-cell immunoglobulin and mucin-domain containing 3 (TIM3), and CCR4.