Fig. 7. Characterisation of spontaneous tumours of K14NLef1 mice and model of their development. Paraffin-embedded sections of sebaceous adenoma from K14NLef1 mice (A,B,D) and chemically induced squamous carcinoma of wild-type mouse (C) were immunostained with anti-Myc epitope (A), anti-ß-catenin (B), or anti-cyclin D1 (C,D) antibodies. Diffuse staining of stroma and sebocytes in C,D is nonspecific. (E) In situ hybridisation for Ptc in sebaceous adenoma (arrowheads) and overlying interfollicular epidermis (arrow indicates expression in hair follicle). (F) Schematic model of consequences for differentiation and tumorigenesis of activating (green; Gat et al., 1998) or repressing ß-catenin signalling (red) in mouse skin. Scale bars: 50 µm in A,C,D; 25 µm in B; 100 µm in E.