Objective To investigate the difference of minichromosome maintenance protein 2 (MCM2) mRNA expression among colonic normal mucosa, colonic adenoma and carcinoma. Methods The expressions of MCM2 mRNA were determined by real-time RT-PCR in 12 colonic normal mucosa, 33 colonic adenomas and 12 colonic carcinomas. Data were evaluated by relative expression software tool (REST-XL). Results The expressions of MCM2 mRNA elevated in turn by colonic normal mucosa, adenoma and carcinoma. The expression of MCM2 mRNA in colonic carcinomas was significantly higher than that in adenomas， as well as in normal mucosa (P=0.001), while the difference of MCM2 mRNA expressions between adenoma and normal mucosa was insignificant (P=0.184). Conclusion The difference of MCM2 mRNA expressions between adenoma and carcinoma indicated the potential value on early diagnosis for colonic carcinoma.