Metastatic spread of human tumour implanted into thymectomized, antithymocyte serum treated hamsters.

The growth and metastatic spread of human tumours in immunosuppressed hamsters is described. A variety of human tumours were transplanted to the flank or the cheek pouch of the hamsters. Immunosuppression was obtained by combined thymectomy and ATS treatment. In the period up to 4 months after implantation, metastases to the lungs were observed with carcinomata of breast, colon, larynx and kidney; also melanoma, rhabdomyosarcoma, fibrosarcoma and teratoma of testis. Fourteen of 20 different tumours implanted metastasized to the lungs. Only 2 tumours, a hypernephroma and a melanoma, became established at the site of implantation; the remainder regressed even though the tumour was proliferating in the lungs.