Microvessel density, cyclo-oxygenase 2 expression, K-ras mutation and p53 overexpression in colonic cancer

Background: Tumour angiogenesis, cyclo-oxygenase (COX) 2 expression, K-ras mutation and p53 overexpression are commonly involved in colorectal tumorigenesis, but their interrelationship and clinicopathological effects remain inconclusive. Methods: Clinicopathological data from 114 consecutive patients with primary stage III colorectal cancer were evaluated prospectively. Microvessel density (MVD) of the tumour was defined by counting the number of microvessels in hotspots, visualized by inummocytochemical staining of endothelial CD34. K-ras mutation was analysed by the restriction enzyme cleavage method. COX-2 expression and p53 overexpression were determined by immunocytochemistry. Results: Increased MVD in hotspots was significantly associated with COX-2 expression (P < 0.001), K-ras mutation (P = 0.007) and p53 overexpression (P = 0.006). COX-2 expression was not associated with either K-ras mutation or p53 overexpression. Clinicopathologically, greater MVD and COX-2 expression were significantly associated with vascular invasion of cancer cells (MVD, P = 0.027 and COX-2 expression, P = 0.006), but p53 overexpression and K-ras mutation were not. Multivariate analysis indicated that greater MVD (P = 0.002) and p53 overexpression (P = 0.016) were significant independent predictors of tumour recurrence, whereas COX-2 expression (P = 0.634) and K-ras mutation (P = 0.356) were not. Conclusion: Tumour angiogenesis may be associated with tumour metastasis and is significantly influenced by K-ras mutation, p53 overexpression and COX-2 expression in patients with colonic cancer.