METTL14 and nonpapillary renal cell carcinoma: Given the fact that the METTL3 and METTL14 proteins are in charge for m6A installation, we next performed western blot assay with 16 pairs of ccRCC tissues and normal tissues used, which confirmed the downregulated expressions of these two important m6A writers in ccRCC at protein level (Fig. 4m).