CXCR4 and nonpapillary renal cell carcinoma: Here, we noticed that CXCR4 tended to be enriched in ccRCC tissues and cell lines, compared to their normal counterparts, which were supported by the Pan-cancer analysis results in kidney renal clear cell carcinoma (KIRC) and kidney renal papillary cell carcinoma (KIRP), indicating that aberrantly expressed CXCR4 was closely associated with ccRCC progression, which were in accordance with the previous literatures [21–24].