微卫星DNA序列在鉴别肿瘤转移细胞中的应用

目的利用微卫星ＤＮＡ研究人乳腺癌裸鼠模型中的遗传稳定性及其早期发现微转移的方法。方法将人乳腺癌移植于裸鼠乳腺脂肪垫，提取组织ＤＮＡ，在３个微卫星位点（Ｄ１４Ｓ６８、Ｄ１８Ｓ６９、Ｄ２０Ｓ１９９）对人乳腺癌、裸鼠移植瘤及其转移灶进行ＰＣＲ分析。结果裸鼠移植瘤及其转移灶在３个位点与人乳腺癌具有相同的微卫星ＤＮＡ。结论裸鼠移植瘤及其转移灶来源于人乳腺癌。人乳腺癌在异种移植、裸鼠体内连续传代及转移，体外培养过程中具有遗传稳定性。本法是一种简单、敏感、特异性强的鉴别肿瘤转移细胞的方法。

THE USE OF MICROSATELLITE DNA MARKERS FOR DISTINGUISHING METASTATIC TUMOR CELLS

Objective To study the genetic stability and to establish a method for detection of micrometastasis using microsatellite DNA in human breast cancer xenograft in nude mice.Methods Fresh tissue of human breast cancer was xenotransplanted in nude mice orthotopically. Genomic DNA extracted from tissues of human breast cancer, xenotransplanted tumors and metastatic foci in nude mice were PCR amplified at three microsatellite loci(D14S68,D18S69,D20S199) and were analysed by electrophoresis and silver stain on PAGE.Results Microsatellite DNA in genome of the xenotransplanted tumors and metastatic foci in nude mice were identical with that of the human breast cancer.Conclusion This study has demonstrated in nude mice the xenotransplanted tumors and metastatic foci that originated from human breast cancer. The genetic stability in human breast cancer is evident in the processes of xenotransplantation, serial passages in nude mice, metastasis and in vitro culture. This method is sensitive and specific for the discrimination of metastatic tumor cells.