In addition, we verified the low expression status of TJP2 and ERK2 in ccRCC and their relationship with ccRCC metastasis by immunohistochemical staining in 60 pairs of ccRCC and AN tissue and Western Blot in eight pairs of fresh ccRCC and AN tissue (Fig. 6G, H). This evidence concerns the gene MAPK1 and nonpapillary renal cell carcinoma.