Cyclooxygenase-2 expression correlates with tumor neovascularization and prognosis in human colorectal carcinoma patients

The role of cyclooxygenase-2 (COX-2) in tumor neovascularization of human c olorectal carcinoma is yet to be delineated, One hundred colorectal carcino ma specimens were evaluated for COX-2 expression and CD34-stained microvess el density (MVD) by immunohistochemical methods, The relationships between COX-2 expression and clinicopathological feature of the patients, MVD, and survival time were analyzed, Increased COX-2 expression was significantly c orrelated with pathologically unfavorable findings such as tumor size (>3,0 cm), tumor differentiation (poor, moderate > well differentiated), number of metastatic lymph nodes (greater than or equal to 4), and Dukes' stage (D ukes' B, C, and D), Larger number of microvessels congregated around the CO X-2-expressing area, and the Spearman rank correlation test showed a strong correlation between COX-2 expression and tumor MVD (P < 0,0001), Patients with COX-2-positive tumors had a significantly (P = 0,037, by log-rank test ) shorter survival time than those with negative tumors did. In the multiva riate analysis, however, only Dukes' stage and number of metastatic lymph n odes remained as independent prognostic factors. Augmented tumor neovascula rization may be one of the several effects of COX-2 responsible for poor pr ognosis in human colorectal carcinoma patients.