Induction of benign and malignant lip tumors in Syrian hamsters by topical application of N-nitrosobis(2-oxopropyl)amine and N-nitroso(2-hydroxypropyl)(2-oxopropyl)amine

Weekly topical application of equitoxic doses of N-nitrosobis(2-oxopropyl)amine (BOP) or N-nitroso(2-hydroxypropyl)(2-oxopropyl)amine (HPOP) to lip and/or vagina of female Syrian hamsters led to the development of papillomas and carcinomas of the lip, papillomas of the vagina, and tumors of internal organs. The relative incidence of the tumor types is affected by the dose of BOP or HPOP administered. BOP is excreted unchanged and as HPOP in the saliva of Syrian hamsters injected subcutaneously with BOP and pilocarpin. This result may help to explain preliminary observations that subcutaneously injected BOP and pilocarpin also lead to lip tumors.