Squamous cell carcinoma induced by DMBA/TPA in mice. SCC mice were treated according to a chemical carcinogenic protocol using DMBA and TPA for 16 weeks. Papilloma incidence (A) and tumor volume (B) were determined in SCC mice. Each value represents mean ± SEM of 9 different mice. *P<0.05, **P<0.01 and *** P< 0.001. Panels C, E and G are representative photomicrographs of dorsal tissue from SCC mice. Haematoxylin and eosin staining of skin tissue sections from BALB/c mice 4(D), 8(F) and 16 (H) weeks after chemical carcinogenesis. Data are from one experiment that is representative of three independent experiments (n = 9 mice per group). Arrows indicate inflammatory cells.