Expression of human VEGF proteins in tumor tissues of gastric and colorectal cancer xenograft models. (A) The level of human VEGF (black bar) and VEGF165b (open bar) protein in bevacizumab-sensitive and bevacizumab-insensitive tumor tissues was quantified by ELISA (n = 4/group). (B) The quantity of VEGF was compared between the two groups. The averages were shown as bars and numeric values. *: P < 0.05 vs. sensitive group by Wilcoxon test.