METTL13 and nonpapillary renal cell carcinoma: Results of METTL13 protein expression obtained from 5 ccRCC cell lines (OS-RC-2, 760-P, ACHN, Caki-1 and 786-O) and a normal renal proximal tubule epithelial cell line (HK-2) showed that METTL13 was significantly underexpressed in most of the cancer cell lines (Fig. 2a).