Figure 4.

Histopathological analysis and tumor size of the skin papillomas. A: Skin papillomas were classified according to their volume and depicted as a percentage of the total number of tumors for the WT, Skp2^−/− (Skp2 KO), p27^−/− (p27 KO), and Skp2^−/−/p27^−/− (Skp2/p27 KO) mice. Immunostaining with anti-BrdU antibody of representative sections of Skp2^−/− (B) and Skp2^−/−/p27^−/− (C) papillomas. Representative paraffin sections of papillomas at 30 weeks of promotion from WT (D), Skp2^−/− (E), p27^−/− (F), and Skp2^−/−/p27^−/− (G) mice. Original magnification, ×10. Skp2^−/− and Skp2^−/−/p27^−/− mice exhibit only moderate dysplasia in well-differentiated tumors. A section of a WT papilloma exhibits moderated dysplasia and some anaplastic areas, whereas severe dysplasia and anaplastic areas were observed in the p27^−/− tumors.