ENHANCED CD34 EXPRESSION OF SINUSOID-LIKE VASCULAR ENDOTHELIAL-CELLS IN HEPATOCELLULAR-CARCINOMA

The immunohistochemical expression of CD34 (human hematopoietic stem c ell and endothelial cell marker) and laminin were studied in chronic l iver diseases and hepatocellular carcinoma (HCC) to elucidate whether their expression reflected phenotypic differences between non-cancerou s sinusoids and sinusoid-like tumor vessels. In normal liver, hepatic sinusoids were always negative for CD34 and laminin. In chronic hepati tis and cirrhosis, the two antigens were sparsely expressed in capilla rized sinusoids at periportal and perinodular area. In advanced HCC, C D34 was strongly and diffusely expressed by the endothelial lining of sinusoidlike tumor vessels. However, early-stage HCC showed a wide spe ctrum of CD34 expression from negative to focal and diffuse, strongly positive staining in sinusoid-like vessels. Laminin was strongly expre ssed in advanced HCC but not in early-stage HCC. The results indicate that the enhanced expression of CD34 by sinusoidal endothelial cells m ay reflect the phenotypic change of endothelial cells in chronic liver diseases and HCC, and that the expression may correlate with the proc esses of angiogenesis induced by hepatocarcinogenesis.