Heteroteansplantation of a human mammary carcinoma to the mouse mutant nude.

A human mammary carcinoma was heterotransplanted to athymic nude mice. Viable tumour tissue was maintained throughout the observation periods which, because of the limited life span of nude mice, were relatively short; in one animal surviving for a longer period, actual tumour growth was observed. It is concluded that human mammary carcinoma is capable of growing in nude mice but, because of the frequently low growth rate of these tumours, prolonged periods of observation are required in order to reveal such growth.