Drug testing using a soft agar stem cell assay on patient and xenograft tumor material

Since 1981 we have received 50 tumor samples from 10 different sites; over half were breast or ovary. Of the 27 that were considered suitable for cloning, 11 produced colony formation and 6 of these were drug tested. One ovarian granulosa cell tumor and its xenograft (V7) were tested against several cytotoxic agents. During a period of 16 months, sensitivity to cisplatin was relatively stable but sensitivity to vinblastine was markedly changed when the original tumor cells and original cells stored in liquid nitrogen were compared with xenograft cells. These changes may be related to patient treatments prior to tumor sample collection. This xenograft V7 exhibited chromosome karyotype and iso-enzyme Glucose-6-phosphate dehydrogenase consistent with it being of human origin. Gross histology of original tumor and xenograft were similar. Chemosensitization in vivo of a breast xenograft (Hx99) to melphalan by misonidazole was investigated. Misonidazole at a total dose of 0.5 g/kg given prior to melphalan (14 mg/kg) was an effective chemosensitizer.