1. 2-Aminodiphenylene oxide is hepato-carcinogenic to male and female C57 × IF F1 hybrid mice and a bladder carcinogen in the male. 2. 4-Aminodiphenyl is hepato-carcinogenic to C57 × IF mice but only induced a single papillary Grade I carcinoma of a bladder in 31 surviving males and none in 27 females. 3. There was no significant difference in the degree of hyperplasia induced by 2-aminodiphenylene oxide in the interval between the beginning of the experiment and withdrawal of the diet after 45 weeks. At that time the hyperplasia was still appreciably dependent on the presence of the chemical. 4. Administration of a limited dose of 2-aminodiphenylene oxide followed by the implantation of a paraffin wax pellet into the lumen of the bladder led to significantly more carcinomas of the bladder epithelium than were obtained in mice given the chemical alone or followed by a “mock” implantation, or in mice implanted with a pellet alone. 5. The significance of these results to the importance of hyperplasia in the induction of tumours of the bladder is discussed. It is suggested that hyperplasia may be of two types (dependent or non-dependent on the presence of the chemical) with different significance in the carcinogenic process.
ASJC Scopus subject areas
- Cancer Research