Cyclooxygenase-2 Expression Predicts Prognosis in Astrocytic Tumors

ABSTRACT

OBJECTIVE: Cyclooxygenase-2, the inducible isoform of prostaglandin H synthesis, has been implicated in the growth and progression of a various human cancer. Although COX-2 overexpression has been observed in humangliomas, the prognostic or clinical relevance of this overexpression has rarely been investigated to date. METHODS: We examined COX-2 expression by immunohistochemistry in tumor specimens from 25 patients with low- and high grade astrocytomas and correlated the grade of COX-2 expression with patients survival. RESULTS: Immunohistochemical staining results were as follows negative staining, N=4(16%), positive staining, N=21(84%). Results of low grade astrocytoma(N=10) were as follows negative staining, N=3(30%), weak positivestaining, N=7(70%). Anaplastic astrocytomas(N=4) as follows negative staining, N=1(25%), weak positivestaining, N=3(75%). Glioblastomas(N=11) as follows negative staining, N=0(0%), weak positive staining, N=5(45%), strong positive staining, N=6(55%). As a group, tumors with higher rate of cell proliferation tended to have increased expression of COX-2. The percentage of COX-2 expression were associated with a worse survival rate(p=0.0028), and the grade of astrocytic tumors(p=0.001). These findings indicate that high COX-2 expression in tumor cell is associated with clinically more aggressive gliomas, and is a strong predictor of poor survival. CONCLUSION: Our study provides evidence that COX-2 is up-regulated in the majority of high-grade gliomas and that increased COX-2 expression is a significant negative predictor of survival and selective COX-2 inhibitors may have a potential role as an adjuvant therapy of astrocytic tumors.