〔目的〕检测微卫星不稳定性(MI)在子宫内膜癌中的阳性率及其与 p53蛋白表达的相关性和临床意义。〔方法〕常规方法提取了36份子宫内膜癌新鲜冰冻组织和相应外周血的DNA ,利用PCR技术扩增 ,其分别位于5号、10号、12号、17号和18号染色体上的6个微卫星位点 ,包括5(D5S107)、10(D10S197)、12(D12S79、D12S95)、17(D17S513)和18(D18S58)。用免疫组织化学方法检测其石蜡包埋组织切片中的p53蛋白表达情况。〔结果〕MI者发生率为27 7 %(10/36) ,其中3例乳头状浆液性子宫内膜癌均未表现MI。子宫内膜样癌的MI发生率为30 3 %。MI与p53蛋白表达呈负相关 ,与患者的年龄、临床分期、组织分化程度以及有无淋巴结转移无明显相关性。〔结论〕MI是子宫内膜样癌较普遍的基因异常 ,与p53基因的作用机理不同 ,是子宫内膜样癌发生、发展的又一分子生物学机制 ,对理解子宫内膜癌的发生、临床分类、患者预后及指导治疗具有重要意义。 [Objective] To detect the positive rate of microsatellite instability (MI) in endometrial carcinoma and its correlation with p53 protein expression and clinical significance. [Methods] Thirty-six fresh frozen tissues of endometrial cancer and corresponding peripheral blood DNA were extracted by conventional methods and amplified by PCR, which were located on chromosomes 5, 10, 12, 17 and 18, respectively A microsatellite locus, including 5 (D5S107), 10 (D10S197), 12 (D12S79, D12S95), 17 (D17S513) and 18 (D18S58). Immunohistochemistry was used to detect the expression of p53 protein in paraffin-embedded tissue sections. [Results] The incidence of MI was 27.7% (10/36), of which 3 cases had no papillary serous endometrial carcinoma. The incidence of MI in endometrioid carcinoma was 30 3%. There was a negative correlation between MI and p53 protein expression, which had no significant correlation with age, clinical stage, histological differentiation and lymph node metastasis. Conclusion MI is a common genetic abnormality of endometrioid carcinoma. Different from the mechanism of action of p53 gene, MI is another molecular biological mechanism of the development and progression of endometrial carcinoma. To understand the occurrence of endometrial carcinoma, Clinical classification, prognosis and guiding therapy are of great significance.