The influence of preliminary irritation by acetic acid or croton oil on skin tumour production in mice after a single application of dimethyl-benzathracene, benzopyrene, or dibenzanthracene.

TLDR: It is considered that proliferating epidermal cells are more susceptible to the action of the carcinogens perhaps during replication of DNA.

Abstract: Groups of mice were given a single application of acetic acid to one side of the skin of the back. Other groups were given an application of croton oil to the whole area of the skin of the back, a control group had no application of croton oil. At the same time as, 24 hours, 72 hours, or 9 days after the application of acetic acid or croton oil, the mice were given a single application of one of the carcinogenic hydrocarbons DMBA, BP or DBA, to the whole area of the skin of the back. The number of tumours produced was greater in areas that had the preliminary treatment with acetic acid or croton oil at the same time or 24 hours before the carcinogen. There was a doubtful effect at an interval of 3 days and no effect at 9 days. It is considered that proliferating epidermal cells are more susceptible to the action of the carcinogens perhaps during replication of DNA.