Immunohistochemical expression of cycloxygenase-2 in astrocytoma: correlation with angiogenesis, tumor progression and survival

Abstract

Aim: Cyclooxygenase-2 (Cox-2) appears to play a role in the regulation of progression, invasiveness and angiogenesis of various neoplasms. Experimental studies have indicated that COX-2 regulate angiogenesis by modulating vascular endothelial growth factor (VEGF) production. The aim of this study was to evaluate the immunohistochemical expression of COX-2 in astrocytoma, in relation to VEGF expression, microvessel density (MVD), clinicopathologic factors and patient survival.

Material and methods: 26 paraffin blocks of astrocytoma, with representative tissues and sufficient follow-up data, were evaluated immunohistochemically for protein marker expression.

Results: COX-2 expression was detected in 21 (80.7%) of 26 astrocytomas with an increased expression in grade IV (100%) as compared to grades II (63.6%) and III (83.3%) (p < 0.001), (r=0.64). A positive correlation was observed between the immunoreactive scores of COX-2, VEGF (p < 0.001), (r=0.61) and MVD (p < 0.001), (r=0.72). Also COX-2 expression was significantly associated with poor survival (p < 0.001), (r=0.58), but did not show significant difference among patient age, sex and tumor location.

Conclusion: COX-2 is up-regulated in the majority of high-grade astrocytomas and may contribute to astrocytic tumorigenesis by promoting new vessel formation. Moreover, increased COX-2 expression is a significant negative predictor of survival. COX-2 inhibitors may represent an important therapeutic target.