CXCR4 and prostate carcinoma: Consistent with our earlier results indicating that CXCL8 signaling up-regulated CCR2 and CXCR4 expression in prostate cancer cells, we observed that the reduction in autocrine CXCL8 expression resulted in a significant decrease in CCR2 and CXCR4 mRNA expression in PC3-120 cells (Fig S5C).