Résumé
<p><b>OBJECTIVE</b>To investigate spontaneous metastasis, micrometastasis and genetic stability in human breast carcinoma xenografts in nude mice.</p><p><b>METHODS</b>Intact tissue from surgical specimens from breast carcinoma patients was xenografted into nude mice and transplanted from generation to generation. Cells from the xenografts were cultured in vitro and retransplanted into nude mice. Microsatellite DNA in the genome of human breast carcinomas, xenotransplanted tumors and metastases in nude mice were analyzed at three microsatellite loci.</p><p><b>RESULTS</b>The tumorigenicity of orthotopic xenotransplantation was 88.6% (31/35), with a metastatic rate of 41.9% (13/31). Cells from xenotransplants were successfully cultured in vitro. The taking rate of retransplantation into nude mice and the spontaneous lung metastasis rate were both 100% (10/10). Microsatellite DNA sequences in the genome of xenotransplanted tumors and metastases in nude mice were identical with that of the original human breast carcinoma at three microsatellite loci.</p><p><b>CONCLUSIONS</b>Tumorigenicity and metastatic potential can be improved in human breast carcinoma xenografts using intact fresh tumor tissue and orthotopic grafts. Xenotransplanted tumors and tumors after serial passage maintained the genetic stability. The detection of microsatellite DNA may identify micrometastases in a nude mouse model.</p>