Figure 5
From: Synergistic functions of E2F7 and E2F8 are critical to suppress stress-induced skin cancer
Atypical E2Fs inhibit tumor growth and progression in DMBA/TPA-induced carcinogenesis. (a) Two weeks after a single dermal application of DMBA (initiation), bi-weekly applications of TPA (promotion) were performed for a period of 15 weeks, as indicated by arrows. (b) Average number of tumors per mouse, classified by tumor diameter, during the first 12 weeks of TPA treatment (control n=20; 78Δ/Δ n=19; 78Δ/Δ1−/− n=18). *P<0.05 compared with control, #P<0.05 vs 78Δ/Δ, one-way ANOVA on repeated measurements with Bonferroni correction for multiple testing. (c) Cumulative incidence of large tumors (diameter >8 mm; control n=20; 78Δ/Δ n=19; 78Δ/Δ1−/− n=18). *P<0.001 vs control, #P<0.001 vs 78Δ/Δ, log-rank, Mantel–Cox test. (d) Average papilloma growth rates (control n=99; 78Δ/Δ n=85; 78Δ/Δ1−/− n=71). *P<0.05 vs control. (e) Quantification of malignant progression by histological classification of skin tumors. The following categories were distinguished: hyperplasia; papilloma; carcinoma in situ; SCC grade 1; grade 2; grade 3. *P<0.001 vs control, chi-square test. (f) Representative photos of tumor stages quantified in e. Scale bars indicate 1 mm in low-magnification pictures and 50 μm in high-magnification pictures. (g) Representative photos of lymph-node metastasis observed in 78Δ/Δ1−/− mice. Scale bar indicates 1 mm in low magnification and 200 μm in high-magnification picture.
