OBJECTIVETo investigate the expression differences of minichromosome maintenance 2 (MCM2) mRNA and protein among colon adenocarcinoma, colon adenoma and normal mucosa, and among different clinicopathological types of adenomas.

METHODSFifty specimens, including 33 colonic adenomas, 12 colonic adenocarcinomas and 5 normal colonic mucosa were selected. Each specimen was divided into two parts, one for immunohistochemistry and the other for real-time RT-PCR. Expression differences of MCM2 mRNA among the colonic adenocarcinoma, adenoma and normal colonic mucosa were evaluated by REST-XL software.

RESULTSThe expression of MCM2 was observed in the basal third to half of the colonic crypts in normal mucosa, while throughout the epithelium in the colonic adenocarcinomas and adenomas. However, the expression of MCM2 mRNA in the adenocarcinomas was significantly higher than that in the adenomas(P=0.001). The MCM2 mRNA expression was elevated in the adenoma with villous type, in the conditions of high-grade dysplasia, larger size, sessile morphology and in patients of older ages, but the difference was not significant by REST-XL (P>0.05).

CONCLUSIONThe difference of MCM2 expression between the adenoma and the adenocarcinoma indicates its potential value in the early diagnosis of colonic cancer.