SCID mice: a suitable model for experimental studies of urologic malignancies

In vivo studies on human malignant tumors are limited because of a lack of suitable animal models. In this study, the usefulness of SCID (severe combined immunodeficiency) mice, deficient in functions of both T- and B-lymphocytes, was evaluated. Inbred SCID mice were kept in isolated cages and 2 x 10(7) cells of KU-7, an established bladder carcinoma cell line, were inoculated in the subcutaneous tissue of the flank region of six SCID mice. Athymic nude mice were inoculated by the same method and served as the controls. The KU-7 cells were taken within 14 days in the injected region in all six SCID mice, while in only five out of eight nude mice. Tumors subsequently formed at the site of inoculation in these mice were confirmed to be transitional cell carcinomas histologically and intra-abdominal metastases were noted in two SCID mice. We conclude that SCID mice provide an ideal in vivo model for experimental studies of human urologic malignant tumors.