CXCR4 and nonpapillary renal cell carcinoma: As shown in Figure 6A, the percentages of genetic alterations in CXCRs of ccRCC ranged from 1.8 to 10% for single genes (CXCR1, 1.8%; CXCR2, 1.8%; CXCR3, 6%; CXCR4, 6%; CXCR5, 4%; CXCR6, 10%; CXCR7, 7%).