Correlation of plasma level and immunohistochemical expression of vascular endothelial growth factor in patients with advanced colorectal cancer

Abstract

Background: Vascular endothelial growth factor (VEGF) is thought to be the most potent angiogenic factor and may contribute to the progression of various cancers. In colorectal cancer, the immunohistochemical expression of VEGF is reported to be an independent prognostic factor, and elevated plasma levels of VEGF are reported to be a prognostic marker. The purpose of this study is to evaluate whether plasma levels of VEGF correlate with its immunohistochemical expression and with microvessel density (MVD) in patients with colorectal cancer.

Materials and methods: Thirty-one patients with advanced colorectal cancer, who underwent surgery between February 1998 and April 2000, were included in this study. We measured the preoperative plasma levels of VEGF using the ELISA kit and immunostained the resected specimens for VEGF and CD34, as a marker of MVD. We then investigated the correlation among plasma levels of VEGF, expression of VEGF and MVD, and between these three factors and several clinical features.

Results: The plasma levels of VEGF were significantly associated with liver metastasis, the immunohistochemical expression of VEGF was significantly associated with lymph node metastasis and TNM stage, while MVD was significantly associated with lymph node metastasis, depth of invasion and TNM stage. Among the 3 parameters for angiogenesis studied, the plasma levels of VEGF significantly correlated with its immunohistochemical expression, and immunohistochemical expression of VEGF significantly correlated with MVD. There was no significant correlation between plasma levels of VEGF and MVD.

Conclusion: Measuring plasma levels of VEGF is a good predictor of the immunohistochemical expression of VEGF in patients with advanced colorectal cancer, and may be a better indicator for tumor VEGF levels, since plasma levels can be measured much more quickly than expression levels.