SUV39H1 and nonpapillary renal cell carcinoma: Suppressor of variegation 3-9 homolog 1 (SUV39H1)-encoding histone H3 lysine-9 methyltransferase is often upregulated in ccRCC tumors, and its expression level is an independent risk factor affecting prognosis; its deficiency regulates the H3K9me3 state of the dipeptidyl peptidase-4 (DPP4) gene promoter, causing DDP4 upregulation and ferroptosis (95).