ObjectiveTo detect the expression of hMLH1, hMSH2 or hMSH6 protein in sporadic colorectal carcinoma (SCRC) and analyze the relationship of its expression to clinicopathologic parameters of patients with SCRC. MethodsTwo hundred and sixty-three patients with SCRC were studied, who underwent surgery in the Department of General Surgery, the Air Force General Hospital; and the Department of Colorectal Surgery, Beijing Cancer Hospital from March 2008 to March 2012. All the patients were diagnosed by histological examination without chemoradiotherapy before operation. Immunohistochemistry was used to detect the hMLH1, hMSH2 or hMSH6 protein expression in the tumor tissues from 263 cases of SCRC. The relationship of its expression to clinicopathologic parameters was analyzed. ResultsThe loss rates of hMLH1, hMSH2, and hMSH6 expressions in the tumor tissues from 263 patients with SCRC were 13.3% (35/263), 12.2% (32/263), and 28.9% (76/263), respectively. The loss rates of hMLH1/hMSH2, hMLH1/ hMSH6, hMSH2/hMSH6, and hMLH1/hMSH2/hMSH6 expressions were 3.4% (9/263), 10.2% (27/263), 6.8% (18/263), and 3.4% (9/263) corresponding. The loss rate of hMLH1 expression in the high differentiated adenocarcinoma tissues was significantly higher than that of the moderate to low differentiated adenocarcinoma or mucous carcinomas tissues (P < 0.01). The loss rate of hMLH2 expression in the tissues of tumor size more than 5 cm was significantly higher than that in the tissues of tumor size less than 5 cm (P < 0.05). The loss rate of hMSH6 expression in the male patient was significantly higher than that of the female patient (P < 0.01) and which in the tumor tissues of less lymph node metastasis was significantly higher than that in the tissues of the more lymph node metastasis (P < 0.01). ConclusionsThe hMLH1, hMSH2, or hMSH6 gene expression deletion is common in SCRC and the relation with the clinical pathology of SCRC is obviously different from Lynch syndrome. Therefore, the effects of hMLH1, hMSH2, and hMSH6 expressions on the development, invasion, and metastasis of SCRC are different from Lynch syndrome too.