Chemical induction of skin tumors in hairless (Skh-1) mice in view of photochemotherapy

摘要

The effects of a classic two-stage carcinogenesis protocol on the formation of skin tumors in hairless female SKH-1 mice were studied in order to carry out photochemotherapy on the mice bearing tumors later. Mice were initiated with a single application of 100 nmol of 7,12- dimethylbenz$LB@a$RB@anthracene in 0.1 ml acetone and promoted one week later, twice weekly with topical applications of 1.8 nmol (first protocol) or 5 nmol (second protocol) 12-o- tetradecanoylphorbol-13-acetate in 0.1 ml acetone. The first tumors occurred between 4 and 6 weeks after the beginning of the promotion process depending on the protocol and the percentage of mice bearing tumors increased and reached 41% and 100% at the end of the treatment respectively for the first and the second protocol. Depending on the protocol, the tumor yield was 0.8 for the first one and approximately 10 for the second one whereas we expected 3 tumors per mouse. Histology of some skin tumors revealed that all were papillomas, hence benign tumors. These papillomatous lesions seem characteristic of a viral attack as seen in other strains of mammals including humans.