A strain of hairless mouse susceptible to tumorigenesis by TPA alone: studies with 8-methoxypsoralen and solar simulated radiation.

Hairless albino mice were painted with 8-methoxypsoralen (8-MOP) and exposed to solar simulated radiation (SSR) for 0, 3 or 6 weeks and subsequently treated with the promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). TPA was highly tumourigenic in non-pretreated mice. Pretreatment with 8-MOP + SSR did not increase this level of tumorigenesis. It is proposed that 8-MOP + SSR tumour induction was the result of promotion of innate initiated cells and that this mouse strain might be useful as a promoter testing model.