探讨同一食管癌患者食管的鳞状细胞癌组织、不典型增生组织、正常鳞状上皮组织中错配修复基因1（human mutl homolog 1，hMLH1）的蛋白表达情况，深入研究它与食管鳞状细胞癌发生发展的关系。方法：取92例食管鳞状细胞癌患者的病变组织，其病理切片中鳞状细胞癌组织、不典型增生组织和正常鳞状上皮组织均存在，采用免疫组织化学的方法，检测hMLH1蛋白在3种不同组织中的表达，并分析其与性别、年龄、分化程度、浸润深度、肿瘤分期、淋巴结转移等临床病理参数之间的关系。结果:hMLH1蛋白在食管鳞状细胞癌组织、不典型增生组织、正常鳞状上皮组织细胞核中的阳性表达率分别为36.96%、56.52%、84.78%，鳞状细胞癌组织和不典型增生组织均显著低于正常食管鳞状上皮组织（P <0.01）。鳞状细胞癌组织中hMLH1蛋白表达阴性者，年龄较阳性者大（P<0.05）； hMLH1蛋白表达与肿瘤分期、淋巴结转移等有明显相关性（P< 0.05）。结论: hMLH1基因缺失可能在早期就参与了食管鳞状细胞癌的发生过程，hMLH1蛋白可能抑制或延缓食管鳞状细胞癌的发生和发展。

To observe the expression of hMLH1 protein in esophagus squamous cell carcinoma, atypical hyperplasia tissue and normal esophagus tissue, so as to discuss the relationship between hMLH1 expression and esophagus carcinogenesis. Methods: The specimens of esophagus squamous cell carcinoma, atypical hyperplasia and normal esophagus tissue were obtained from 92 esophagus carcinoma patients. Immunohistochemistry (IHC) staining technique was used to detect expression of hMLH1 protein. The relationship between hMLH1 expression with clinical parameters, such as gender, age, cancer differentiation level, infiltration depth, tumor stage, lymphatic metastasis, was analyzed. Results: The positive rates of hMLH1 protein in esophagus squamous cell carcinoma, and atypical hyperplasia tissue and normal esophagus tissue were 36.96%，56.52%, and 84.78%,respectively,with the former 2 significantly lower than the latter (P<001). The average age of patients negative of hMLH1 protein in tumor tissues was older than that of patients positive of hMLH1 (P<0.05). There was significant correlation between the expression of hMLH1 with tumor staging and lymphatic metastasis (P<0.05). Conclusion: Deletion of hMLH1 may participate in the carcinogenesis of esophageal squamous cell carcinoma at an early stage.hMLH1 gene may delay and suppress the development and progression of esophageal squamous cell carcinoma.