CXCR4 and nonpapillary renal cell carcinoma: Molecular markers, such as CAIX, PTEN, and CXCR4, have been found to show altered gene expression, gene mutations, and methylation status, and they provide more treatment selections in ccRCC [5], suggesting that investigating novel biomarkers for the early diagnosis, individualized treatment, and prognostic determination of ccRCC is necessary.