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大肠癌微卫星不稳定性及其临床意义
了解大肠癌微卫星不稳定性（microsatellite instability, MI）情况。方法 用6个微卫星位点检测PCR扩增所选位点PCR产物用8%变性聚丙烯酰胺凝胶电泳、银染。结果 60例大肠癌中，20例表现MI，其中11例为复制错误（replication errors, RER）阳性。RER阳性与RER阴性大肠癌患者相比，发病年龄较年轻，一级亲属有恶性肿瘤病史者明显高于RER阴性，倾向位于结肠，呈浸润性生长，Ⅲ～Ⅳ期比例高。5例大肠癌伴大肠腺瘤病例中，4例腺瘤有MI。结论 中国人大肠癌MI发生率介于文献报道之间，MI为大肠癌形成过程中的早期分子事件，RER为肿瘤易感指标之一。
Study of microsatellite instability of colotectal cancer and its clinical significance
XIONG Bin, ZHENG Shu, CAI Xinhan.
Cancer Institute, Zhejiang Medical University, Hangzhou 310009
【Abstract】 Objective To evaluate microsatellite instability (MI) of colorectal cancerin China.Method Replication error (RER) status was examined by using 6 microsatellite loci D2S123, D2S119, D13S160, D8S282, D3S1293 and D18S58. The loci were amplified by PCR technique. The PCR products were separated on denatured polyacrylamide gel and then silver stained.Results Of the 60 cases of colorectal cancer studied, 20 (33.3%) showed MI, 11 cases (18.3%) were RER positive. In 11 RER-positive cases, 4(36.4%) had family history of malignant tumor, while only 8.2% had positive family history in RER-negative cases (P＜0.05). The RER-positive patients were younger, and their cancer occurred more frequently in the colon with invasive type of growth. There were more cancers in Dukes III and IV in the RER-positive patients. In 5 colorectal cancer cases associated with adenoma, MI was detectable in 4 adenomas.Conclusion MI phenotype might be present ubiquitously in sporadic colorectal cancers in China. Its frequency is comparable to that of other reports. MI is a relatively early molecular event in the genesis of colorectal cancers. RER is a useful sign of susceptibility to the development of colorectal cancer.
【Subject words】 Colorectal neoplasms Microsatellite DNA Microsatellite instability
微卫星DNA 是大量随机分布于真核生物整个基因组中的1～6个简单重复核苷酸序列，微卫星不稳定性(microsatellite instability, MI)是指由于复制错误(replication errors, RER)引起的简单重复序列的增加或丢失，其在恶性肿瘤发生发展过程中的作用已受重视，被认为是大肠癌的一种发病机制。我们对60例大肠癌组织的MI进行了研究，并结合临床病理资料，探讨其临床意义。
