A study of tobacco carcinogenesis XX: mastocytoma induction in mice by cigarette smoke particulates ("cigarette tar").

A significant incidence of cutaneous mastocytomas was observed in female mice of CAF1/J and ARS-HA (ICR) strains upon long-term application of cigarette smoke condensate suspensions ("tar"). The mastocytomas were not detected in control groups treated with acetone, benzo(a)pyrene (BaP), tetradecanoyl phorbol acetate (TPA), nor in mice treated once with an initiator dose of 75 mg 7, 12-dimethylbenz(a)anthracene (DMBA). The skin mastocytomas were constantly accompanied by diffuse dermal mast cell infiltration (DDMI), which was also seen in the tumor-free skin of the "tar"-treated mice. These results indicate that mastocytomas were induced by agents present in the cigarette smoke condensate. DDMI might be a precursor of mastocytomas.