Nitric oxide synthase and vascular endothelial growth factor expression in hepatocellular carcinoma and the correlation with angiogenesis

Abstract

To analyse inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), vascular endothelial growth factor (VEGF) protein expression in hepatocellular carcinoma (HCC) and their relation to angiogenesis. Tissue sections from 71 HCC patients were examined immunohistochemically for protein expression of iNOS, eNOS, and VEGF. Microvessal density (MVD) was counted by endothelial cells immunostained by anti-CD34 antibody. Positive iNOS and eNOS immunostaining was detected in 83.1% and 85.9% of HCC respectively. iNOS and eNOS were not detected in normal hepatic tissue. MVD was 34.3 +/- 1.5/HP and 38.6 +/- 1.6/HP in HCC positive for iNOS and VEGF while it was 31.2 +/- 2.8/HP, and 22.4 +/- 2.0/HP in HCC negative for iNOS and VEGF respectively (P < 0.01). A correlation between NOS expression and VEGF in HCC was not observed. iNOS and eNOS may play a role in malignant transformation of post-hepatic cirrhosis. The expression of iNOS and VEGF favors angiogenesis of HCC.