KCNN4 and nonpapillary renal cell carcinoma: It was found that in five ccRCC cell lines (i.e., 769-P, ACHN, Caki-1, Caki-2, and 786-O), KCNN4 mRNA expression was significantly elevated in Caki-1 and Caki-2 cells (Figure 9(a)), with its protein level consistent in Caki-1 and Caki-2 as well (Figure 9(c)).