Carcinogen-induced granulosa cell tumours in NZC/Bl mice.

Old NZC/Bl mice have a high incidence (33%) of unilateral spontaneous granulosa cell tumours. A single topical application of 300 micrograms of 7, 12-dimethylbenz(a) anthracene (DMBA) to the skin at 6 wk of age substantially enhanced the incidence of granulosa cell tumours (95%), a high proportion of which were bilateral. Lesions were detected at a much younger age than in mice not exposed to the carcinogen. Endometrial changes were observed frequently, irrespective of DMBA treatment, and with or without granulosa cell tumours. These observations suggest that the incidence of endometrial hyperplasia, albeit substantially increased by DMBA treatment, is not necessarily dependent on granulosa cell tumour hormonal activity. Telangiectasia, principally affecting vessels in the ovary, uterus and small intestine, was a common finding in DMBA treated mice.