763 Cyclooxygenase-2 in Dukes B Colon Cancer Background/Aims: To demonstrate immunohis- tochemical expression of COX-2 protein in Dukes B colon cancer and to establish a correlation with clinicopathological parameters such as: age, gen- der, gradus, presence of vascular invasion and pa- tient’s overall survival. Methodology: We performed immunohistochem- ical analysis of formalin-ixed, parafin embedded specimens form 152 Dukes B colon carcinomas, using the COX-2 monoclonal antibody. Immuno- histochemical results were scored semi-quanti- tatively. Carcinomas were graded as low or high grade. Survival time was analyzed by Kaplan- Meier method, and the log-rank test was used to assess the differences between groups. For multi- variate analysis, Cox proportional hazard regres- sion model was used to examine several param- eters simultaneously. Results: Univariate analysis showed that posi- tive staining for COX-2, high histological grade; vascular invasion; male gender and age over 60 years, were connected with shorter survival of patients with Dukes B colon cancer (0.023< p<0.001). However, multivariate analysis have shown that the high COX-2 expression in Duke’s B colon cancer was unrelated to overall patient survival (RR=1.4; p=0.311). Conclusion: Expression of COX-2 in tumor epi- thelial cells does not seem to be related to survival in patients with colon cancer Dukes B. ABSTRACT INTRODUCTION Colorectal cancer, one of the most prevalent cancers worldwide, is the third leading cause of cancer related mortality in developed countries (1). Despite improvements in surgical and adjuvant chemotherapy treatment, mortality from colorectal carcinoma (CRC) remains high in Western coun- tries, with metastatic spread to the liver in approxi- mately 50% of patients (2). Although staging remains the most widely used prognostic indicator for CRC, there is increasing evidence that it is insuficient to predict the clinical outcome of patients with CRC, particularly those with intermediate stage diseases (Dukes B, T3, T4, N0, M0), for which clinical management has yet to be standardized. Biological prognostic markers underlying invasion and metastasis may help improve clinical staging and provide useful information for the application of vari- ous novel therapeutic strategies aimed at controlling disease progression and tumor cell dissemination (2). In recent years, the role of a key enzyme in prostaglandin synthesis, cyclooxygenase (COX-2), has been appreciated in cancer development and progression. COX-2 is responsible for the conver- sion of arachidonic acid to prostaglandins and other eicosanoids. In addition to its well-known role in in- lammatory reactions, COX-2 plays a role in tumor progression, angiogenesis, metastasis and abroga- tion of the antitumor immune response (3-6). COX- 2 prevents apoptosis by generation of antiapoptotic PGE2 (7) and PGI2 (8), and by removal of the proa- poptotic substrate arachidonic acid (9). PGE2 in- duces transformations that result in increased Bcl- 2 expression and prolong the cell cycle G1 phase with increased cyclin D1 expression (10). Numer- ous epidemiological studies have indicated that the use of non-steroidal anti-inlammatory drugs, and Željko Šundov 1 , Nenad Kunac 2 , Vesna Čapkun 3 , Marija Kalebić 4 , Nikica Družijanić 5 , Livia Puljak 6 and Snježana Tomić 2 1 Departments of Internal Medicine, 2 Pathology, 3 Nuclear Medicine, 5 Surgery and 6 Histology and Embryology, School of Medicine, University of Split, Croatia. 4 Department of Emergency Medicine, County of Split-Dalmatia, Croatia. Corresponding author: Nenad Kunac, Department of Pathology, School of Medicine, University of Split, Spinčićeva 1, 21000 Split, Croatia Tel.: +38521556486, Fax: +38521389510, E-mail: nenadkunac@gmail.com KEY WORDS: COX-2; Colon cancer; Immu- nohistochemistry; Prognosis FIGURE 1 Cumu- lative survival in relation to COX-2 expression. COX-2 expression Positive --- Negative - - Hepato-Gastroenterology 2011; 58:763-768 © H.G.E. Update Medical Publishing S.A., Athens-Stuttgart