METTL3 and nonpapillary renal cell carcinoma: Considering the high frequency of inactivation of von Hippel-Lindau (VHL) gene and the upregulated hypoxia induced factor-α (HIF- α) in ccRCC, we hypothesize that there may exist a m6A regulatory pathway (VHL-HIF-ZNF217-METTL3/METTL14) in ccRCC cells, leading to the formation and maintenance of ccRCC cancer stem cells.