PECAM1 and neoplasm: Significant anti-angiogenic effects of regorafenib were observed in the investigated colon carcinoma xenografts with a significantly (p<0.05) lower tumor microvascular density, quantified by CD-31 stainings, in the regorafenib-treated therapy than in control group (7.0 ± 2.4 vs. 16.1 ± 5.9).