VEGF, Flt-1, and microvessel density in primary tumors as predictive factors of colorectal cancer prognosis.

Angiogenesis in the primary tumor is known to be necessary for tumor progression in adenocarcinomas of the colon. However, whether angiogenesis in the primary tumors of patients with colorectal cancer affects their prognosis has yet to be fully elucidated. The aim of the present study was to assess the association between selected pathoclinical parameters and overall survival of resectable colorectal cancer patients with the expression of angiogenesis-promoting factors, including vascular endothelial growth factor (VEGF) and Fms-like tyrosine kinase receptor (Flt-1), and microvessel density (MVD) in the primary tumor. VEGF and Flt-1 expression were assessed, as well as MVD (with anti-CD34) by immunohistochemistry in 139 archived primary colorectal cancer tissue samples. These results were compared with the overall survival of the patients and potential prognostic pathoclinical parameters. A higher MVD in the tumors expressing Flt-1 (P=0.04) was identified. However, there was no correlation between the pathoclinical parameters of colon cancer and Flt-1 expression, VEGF expression, or MVD in the tumor. Furthermore, the intensity of VEGF expression, Flt-1 expression and tumor MVD did not correlate with the overall survival of the patients. Therefore, although increased expression of VEGF and Flt-1 was correlated with an increased expression of MVD in the primary tumors of resectable colorectal cancer patients, these factors were not correlated with prognostic pathoclinical factors and overall survival.