Expression Of Platelet-derived Growth Factor B And Its Relation With Microvessel Density In Hepatocellular Carcinoma

Background and Objective: Tumor angiogenesis plays a unique important role on tumorigenesis, development and metastasis in primary hepatocellular carcinoma, which is a common and great threat to human health. Neovascularization may not only provide nutrition and oxygen which are necessities for tumor cell survival, but secret tumor growth factors through paracrine mechanism. In the meantime, tumor cell exerts great impact on vascular endothelial cell via vasoactive substance to accelerate angiogenesis. Many endogenous growth factors relating to tumor angiogenesis have been characterized in vivo in the past decade, including platelet-derived growth factor (PDGF). We aim to investigate the relationship between PDGF-B, microvessel density (MVD) and vascular endothelial cell growth factor (VEGF) in hepatocellular carcinoma (HCC), providing theoretic basis on tumorigenesis, development and metastasis of HCC. Methods HE staining was applied to determine hepatocyte differentiation degree according to Edmondson and Steiner's standard in all fifty-one cancerous tissues obtained from surgical procedure. The expression of PDGF-B and VEGF in the cancerous/paracarcinoma tissues and another twenty control liver tissues were evaluated by immunohistochemhical methods. Microvessels were observed and counted under light microscope through CD34-labelled endothelial cells. Enzyme linked immunosorbent (ELISA) assay method was used to detect preoperative serum PDGF-B concentration in HCC and cholecystolithiasis patients. Results 1. The positive expressions of PDGF-B and VEGF were 54.9%, 64.7% in HCC, 27.5%, 37.3% in paracarcinoma tissues, 5%, 10% in normal liver tissues, respectively. There were significant differences among the three groups. Both PDGF-B and VEGF expression were positively related to differentiation degree, tumor capsule and metastasis, but not to gender, age and tumor size. The average values of MVD were 29.43±4.818, 15.23±2.77 (P<0.01), 14.56±1.96 (P<0.01) among three groups. Correlation analysis revealed the coefficient index of PDGF-B and VEGF was 0.617 (P<0.01), PDGF-B and MVD was 0.445 (P=0.01), VEGF and MVD was 0.331 (P=0.018), respectively. 2. PDGF-B concentration of preoperation serum in HCC and cholecystolithiasis patients was 368.82±245.58, 111.75±58.08, and significant difference (t=4.746, P<0.001) was confirmed. Conclusions 1. PDGF-B and VEGF exhibited low expresssion in normal liver tissue, but high in HCC. 2. Both PDGF-B and VEGF expressions were positively related to microvessel density, differentiation degree, tumor capsule and metastasis, but not to gender, age and tumor size, suggesting that PDGF-B and VEGF may play an important role in the development and metastasis of HCC. 3. Under consideration of positive correlation between PDGF-B and VEGF expression, PDGF-B, as an endothelial growth regulator, may possess certain cooperation with VEGF.