We also examined the expression level of MUC15 in different RCC cell lines, as shown in Fig. 2a, b, compared to HK-2 cell line, Caki-1, ACHN and Rcc42 cells had relatively higher MUC15 mRNA expression, while ACHN, Caki-1 and OS-RC-2 cells had relatively higher MUC15 protein expression among all tested RCC cell lines. This evidence concerns the gene MUC15 and renal cell carcinoma.