Lack of tumor promoting effects of KCB-1, a recombinant human basic fibroblast growth factor, on two-stage skin carcinogenesis in female CD-1 (ICR) mice

Skin tumor promoting and co-promoting potentials of KCB-1, a recombinant human basic fibroblast growth factor, were investigated in a two-stage skin carcinogenesis model using female ICR mice. Animals were allocated to either normal (non-injured) or injured skin groups, and given a single topical application of dimethylbenz[a]anthracene (DMBA) at 100 mu g/mouse to fur-clipped back skin. One week after the DMBA initiation step, mice were injected with KCB-1 (0.4, 4.0 and 40 mu g/mouse, s.c.) and/or 12-O-tetradecanoylphorbol-13-acetate (TPA) at 4.0 mu g/mouse twice a week until the termination at week 20. The treatment with KCB-1 was not associated with any increases of papillomas and hyperplasias in either the normal or the wounded skin cases. High incidences and multiplicities of skin papillomas and hyperplasias developed in TPA-treated groups. The positive control TPA promotion was not influenced by the KCB-1 treatment in the present initiation/promotion protocol. Thus, KCB-1 exerted no tumor promoting effects on mouse skin two-stage carcinogenesis, and also no amplification activity for the established skin tumor promoter TPA.