RESUMO
BACKGROUND: Esophageal cancer is the third most common cancer in Iran. Neoadjuvant chemoradiotherapy (NCRT) is the appropriate treatment for esophageal cancer. AIM: This study investigated the expression of cyclooxygenase (COX)-2 enzyme in normal and tumoral tissues before any treatment in patients with esophageal cancer, this study also assessed the effect of NCRT on the expression of COX-2 enzyme in normal and tumoral tissue in samples derived by surgery furthermore, and this study investigated the relationship between expression of COX-2 enzyme and the pathologic tumor regression grade (PTRG) patients. MATERIALS AND METHODS: In this study, a total of 120 patients admitted to Omid Hospital, Imam Reza Hospitals, and Reza-Mashhad Medical Center, who were treated with NCRT, were recruited and the expression of the COX-2 enzyme in normal and tumoral tissues was assessed by immunohistochemistry before and after treatment by an expert pathologist between zero and 300. PTRG was determined by a pathologist after treatment. RESULTS: The mean levels of COX-2 expression, obtained from tumoral and normal tissue baseline biopsy in patients, were 177.69 and 64.29, respectively, while in surgical specimen were 177.25 and 49.84, respectively. A significant association was found between PTRG of surgical specimen and COX-2 expression in normal tissue (baseline biopsy) at diagnosis (P = 0.034). CONCLUSIONS: The results indicated that expression of COX-2 in tumoral tissues exceeds the expression of COX-2 in normal tissue of the baseline biopsy. Patients with a high expression of COX-2 in baseline tumor biopsies had less response to treatment of pathology compared to patients with lower expression of COX-2 in baseline tumor biopsies.