Expression of CXCR4 and CXCR7 in HCC cell lines and HUVECs. A. RT-PCR was performed on various cell lines to determine CXCR7 and CXCR4 mRNA expression. GAPDH was used as a control. B. Western blot analysis was performed to detect CXCR7 and CXCR4 protein expression. β-actin was used as a control to ensure equal loading. Data shown is representative of three independent experiments. C. The intensity of protein bands was quantified and was shown as relative expression level after normalized by β-actin (n = 3, means ± SD).