Expression and clinical significance of 15-lipoxygenase-1 in colon polyps

FANG Xing-guo; JIN Hai; ZHAO Kui; LI You-feng

Abstract：Objective To observe the expression of 15-lipoxygenase-1 (15-LOX-1) in normal colon muco-sa, hyperplastic polyps, tubular adenoma, villous adenoma and adenocarcinoma of colon, and to investigate the effect of 15-LOX-1 on malignant transformation of colon polyps.Methods Fifteen cases of normal colon mucosa, 25 cases of hyperplastic polyps, 38 cases of tubular adenoma, 30 cases of villous adenoma and 15 cases of adenocarcinoma of colon removed by enteroscopy were selected.15-LOX-1 mRNA expression in all tissues was detected by quantitative RT-PCR, and protein expression by immunohistochemistry and Western blot.Results RT-PCR showed that 15-LOX-1 mRNA expression in normal colon mucosa, hyperplastic polyps, tubular adenoma, villous adenoma and adenocarcinoma of colon was reduced gradually.There was no significant difference between tubular adenoma tissues and villous adenoma tis-sues (P=0.168).There were significant differences among all other tissues (P<0.05).Immunohistochemical detection showed that 15-LOX-1 protein expression was highest in normal colon mucosa tissues, yet lowest in adenocarcinoma of colon.There was no significant difference in 15-LOX-1 protein expression between hyperplastic polyp tissues and nor-mal colon tissues ( P=0.075 ) , as well as between tubular adenoma tissues and villous adenoma tissues ( P=0.125 ) . There were significant differences among all other tissues (P<0.05).Western blot showed that 15-LOX-1 protein ex-pression was highest in normal colon mucosa, yet lowest in adenocarcinoma of colon.There was no significant difference between hyperplastic polyp tissues and normal colon mucosa tissues ( P =0.178 ) .There were significant differences among all other tissues (P<0.05).Conclusions 15-LOX-1 has an effect against carcinogenesis.Reduction or ab-sence of its expression may facilitate malignant transformation of colon polyps.