DEVELOPMENT OF A NEW METASTATIC HUMAN BREAST-CARCINOMA XENOGRAFT LINE

Xenografts originated from human tumours offer the most appropriate re search material for in vivo experimental research, However, primary hu man breast carcinomas are difficult to grow when transplanted in athym ic mice: tumour take is less than 15%, Recently, we have achieved 60% tumour take by injecting tumour cell suspensions mixed with Matrigel, Human breast xenografts originated from primary breast carcinoma also frequently show the potentia: to metastasize spontaneously. In the pre sent study, we generated a human breast carcinoma xenograft line (UISO -BCA-NMT-18) that shows 100% tumorigenicity and 80-100% lung metastasi s when transplanted s.c. in athymic mice. We have studied in detail th e characteristics of the xenograft and the patient's tumour from which the xenograft line originated, Both the xenograft and the patient's t umour showed intense staining for mutant p53 nuclear protein, and high expression of U-PA, PAI and u-PAR. In vivo growth of the xenograft is stimulated by exogenous supplementation of oestrogen. This xenograft is continuously growing in mice and has shown 80-100% metastasis for t he last three successive in vivo passages. This well-characterized, oe strogen-responsive, metastatic breast carcinoma xenograft line will pr ovide excellent research material for metastasis-related research.