Expression of HIF-1alpha and VEGF in colorectal cancer: association with clinical outcomes and prognostic implications

Background: Hypoxia-inducible factor 1 alpha (HIF-1 alpha) and vascular endothelial growth factor (VEGF) are frequently overexpressed in numerous types of cancers and are known to be important regulators of angiogenesis. Until now, few studies have been carried out to investigate the prognostic role of these factors in solid tumors, especially in colorectal cancer (CRC). The purpose of this study was to evaluate the expression of HIF-1 alpha and VEGF in CRC tissues, and to analyze the association of these two factors with several clinical and pathological characteristics, and patients' survival. Methods: Paraffin-embedded tissue samples were retrospectively collected from 71 CRC patients, who received surgical resection between 2001 and 2002, with a median follow-up of 5 years. We examined the patterns of expression of HIF-1 alpha and VEGF by immunohistochemistry method. Statistical analysis was performed with univariate tests and multivariate Cox proportional hazards model to evaluate the differences. Results: Expression of HIF-1 alpha and VEGF was positively observed in 54.93% and 56.34% among the patients, respectively. HIF-1 alpha and VEGF status were significantly associated with tumor stage, lymph nodes and liver metastases (P < 0.05). Expression of both HIF-1 alpha and VEGF remained significantly associated with overall survival (OS) (P < 0.01), and HIF-1 alpha was positively correlative to VEGF in CRC (r = 0.72, P < 0.001). Conclusions: HIF-1 alpha and VEGF could be used as biomarkers indicating tumors in advanced stage and independently implied poor prognosis in patients with CRC. Treatment that inhibits HIF-1 alpha might be a promising targeted approach in CRC to exhibit its potential to improve outcomes in future perspective, just as VEGF targeting has proved to be.