直肠癌是消化道最常见的恶性肿瘤之一，目前外科手术仍然是直肠癌最主要的治疗方法。随着淋巴结廓清范围的扩大，如侧方淋巴结的清扫、全直肠系膜切除术（TME)以及全盆脏器切除术的应用，进展期直肠癌的生存率已有明显改善。但另一方面，大范围的淋巴结清扫及全直肠系膜的完整切除已使许多患者的泌尿及生殖系统功能受到不同程度的影响。患者术后的生活质量是外科医师关注的主要问题，为此，许多外科医生进行了大量的研究工作，既确保根治性，又能最大限度地保留患者的排尿及性功能。近年来国内、外学者通过微创手术、TME结合保留盆腔自主神经（pelvic autonomic nerve preservation，PANP)的直肠癌手术逐渐开展，发现在行直肠癌根治手术时，有效地保留盆腔植物神经并没有明显增加局部复发率及降低5年生存率，取得了很好的效果［1～3］
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.