PTGS2 and hepatocellular carcinoma: Considering that VEGF, COX-2, and CD105 are involved in tumoral angiogenesis and that HCC is a highly vascularized tumor that occurs mainly in chronically diseased livers exhibiting neoangiogenesis, we investigated immunohistochemical expression patterns of VEGF, COX-2, and MVD-CD105 in HCC and surrounding cirrhotic liver tissues.