through aberrant methylation of DNA methyltransferase (DNMT1) and histone methyltransferase (EZH2), they inhibit the expression of MHC-I molecules The above processes lead to a decrease in antigen-presenting capacity on the surface of tumor cells, which in turn hinders the recognition and clearance of tumor cells by CD8+ T cells (75, 76). The gene discussed is DNMT1; the disease is neoplasm.