中文摘要：

背景：为了解实验室常用人癌细胞的微卫星不稳定性情况。目的：从基因组微卫星水平分析各组织来源人癌细胞株的遗传背景差异。方法：取10株指数生长期的人白血病、结肠癌、胃癌、肝癌、肺癌、宫颈癌、膀胱癌细胞及2株人正常细胞（人脐静脉内皮细胞、人皮肤成纤维细胞），提取细胞DNA，对BAT-25，BAT-26，CAT-25，NR-24，SEC-63五个几近单态性的微卫星位点进行PCR扩增，12%聚丙烯酰胺凝胶电泳-银染法对产物进行检测，同时用ABI 3720XL自动测序仪测序。结果与结论：人脐静脉内皮细胞、人皮肤成纤维细胞的5个微卫星位点扩增片段长度具有一致性及稳定性，可作为正常对照。人结肠癌细胞、人膀胱癌细胞在BAT-25、BAT-26、CAT-25或NR-24位点扩增片段长度均较人脐静脉内皮细胞及人皮肤成纤维细胞缩短，缩短产度为7-13 bp，属于微卫星高度不稳定细胞。其他细胞在5个位点扩增片段的长度与人脐静脉内皮细胞、人皮肤成纤维细胞一致，属于微卫星稳定细胞。实验结果揭示了受试人癌细胞基因组微卫星不稳定性水平，为未来选择合适的细胞株进行药物活性筛选等试验奠定了基础。

英文摘要：

BACKGROUND：We aim to understand microsatel ite instability in various human cancer cel s. OBJECTIVE：To analyze the difference in genotypic background of various tissue-derived human cancer cel s based on microsatel ite instability. METHODS：Ten human cancer cel lines at exponential phase were cultured, including human leukemia cel s, colon cancer cel s, stomach cancer cel s, liver cancer cel s, lung cancer cel s, cervical cancer cel s, bladder cancer cel s, and two normal human cel lines （human umbilical vein endothelial cel s and human skin fibroblasts）, and their microsatel ite stability statuses were detected by five quasi-monomorphic markers：BAT-25, BAT-26, CAT-25, SEC-63, NR-24. DNA of 10 human cancer cel lines, human umbilical vein endothelial cel s and human dermal fibroblasts was extracted and amplified by PCR. PCR products were detected by 12%polyacrylamide gel electrophoresis （PAGE）-silver staining and sequenced by ABI 3720XL automatic sequencer. RESULTS AND CONCLUSION：For al the five microsatel ite markers detected, the length of their PCR amplified fragments was nearly identical in human umbilical vein endothelial cel s and human dermal fibroblasts, demonstrating their quasi-monomorphic nature. When compared with human umbilical vein endothelial cel s and human dermal fibroblasts, amplified fragments in human colon cancer cel s （HCT-116） and human bladder cancer cel s （BIU-87） were shortened for 7-13 bp at BAT-25, BAT-26, CAT-25 or NR-24, respectively. No obvious differences were found at al the five loci in other cel s. According to the results, HCT-116 cel s and BIU-87 were considered as cel s with high-level microsatel ite instability. Other cel lines exhibited microsatel ite stability at five loci, and they were considered as microsatel ite stable cel s. Our study revealed status of genome instability in 10 human cancer cel lines, providing references for appropriate cel line selecting in future drug screening and basic medical research.