中文摘要：

背景与目的：上皮型钙黏着蛋白1（cadherin 1，CDH1）和Mut L同源基因1（mut L homolog1，MLH1）在不同肿瘤的发生、发展中起一定作用。本文旨在探讨CDHI和MLH1在甲状腺癌组织中的表达及临床意义。方法：用免疫组织化学SP法检测甲状腺癌（65例）、甲状腺腺瘤（24例）、桥本甲状腺炎（15例）、结节性甲状腺肿（7例）和癌旁正常组织（12例）中CDH1蛋白的表达，以及甲状腺癌（56例）、甲状腺腺瘤（17例）、桥本氏甲状腺炎（13例）、结节性甲状腺肿（8例）和癌旁正常组织（12例）中MLH1蛋白的表达，结合临床病理因素进行分析。结果：CDH1蛋白在癌旁正常组织（83．33％）、结节性甲状腺肿（100％）、桥本甲状腺炎（93．33％）、甲状腺腺瘤（79．17％）及甲状腺癌（47．69％）中表达水平基本呈降低趋势。MLH1蛋白在癌旁正常组织（83．33％）、结节性甲状腺肿（75％）、桥本氏甲状腺炎（76．92％）、甲状腺腺瘤（52．94％）及甲状腺癌（42．86％）中的表达水平呈降低趋势。CDH1和IMLH1蛋白表达水平在甲状腺病变中表达差异均有统计学意义（P〈0．05）。随着甲状腺病变恶性程度升高呈降低趋势，同时CDH1蛋白表达水平降低与PTC和FTC的临床分期、淋巴结转移密切相关。在甲状腺癌中，CDH1和MLH1蛋白表达水平呈正相关（P〈0．05）。结论：CDHI、MLH1蛋白低表达可能与甲状腺癌发生、转移有关；在甲状腺癌中，CDH1与MLH1蛋白表达之间有一定的相关性。

英文摘要：

Background and purpose： It was reported that abnormal expression of cadherin 1 （CDH1） and mut L homolog 1 （MLH1） is often associated with tumor genesis and progression. The study investigated the expression of CDH1 and MLH1, as well as their clinicopathological significance in thyroid cancer. Methods： Immunohistochemical SP method was used to determine the expression of CDH1 in 65 thyroid cancer tissues, 24 thyroid adenoma, 15 Hashimoto＇s thyroiditis, 7 nodular goiter and 12 peri-tumor tissues, and MLH1 in 56 thyroid cancer tissues, 17 thyroid adenoma, 13 Hashimoto＇s thyroiditis, 8 nodular goiter and 12 peri-ttmaor tissues. Results： Expression of CDH1 and MLH1 both decreased from normal tissue （83.33% and 83.33%）, nodular goiter （100% and 75%）, Hashimoto＇s thyroiditis （93.33% and 76.92%）, thyroid adenoma （79.17% and 52.94%） to thyroid cancer （47.69% and 42.86%） differently. There were statistic differences in expressions of CDH1 and MLH1 between the different thyroid pathological tissues （P〈0.05）. Expression level of CDH1 and MLH1 decreased with the malignancy of thyroid cancer. Decreasing of expression of CDH1 correlated with PTC and FTC, also with lymph node metastasis. There was positive correlation between the CDH1 and MLH1 expressions in thyroid cancer （r〈0.4, P〈0.05）. Conclusion： Low expression of CDH1 and MLH1 might be related to the thyroid cancer and its metastasis; there is positive correlation between the CDH1 and MLH1 in thyroid cancer.