Cyclooxygenase-2 is overexpressed in serrated adenoma of the colorectum

PURPOSE: The aim of this study was to clarify whether cyclooxygenase-2 and cyclooxygenase-1 is expressed in hyperplastic polyps and serrated adenomas. METHODS: Forty-nine serrated adenomas and 25 hyperplastic polyps were immu nostained using anticyclooxygenase-2 and anticyclooxyenase-1 antibodies. Cy clooxygenase-2 and cyclooxygenase-1 expression was investigated in all spec imens. RESULTS: Cyclooxygenase-2 was expressed in dysplastic glands in the majority of serrated adenomas. Thirty-five of 49 (71.4 percent) serrated ad enomas exhibited moderate to intense cyclooxygenase-2 immunoreactivity, and 8 of 25 hyperplastic polyps (32 percent) showed weak to moderate cyclooxyg enase-2 immunoreactivity. Cyclooxygenase-1 immunoreactivity was very weak i n all the hyperplastic polyps and serrated adenomas. CONCLUSIONS: These res ults suggest that cyclooxygenase-2 is overexpressed in serrated adenoma of the colorectum. Cyclooxygenase-2 inhibitors will reduce the incidence of se rrated adenomas.