Figure 3. Initiation of tumors with injected TATCre enables comparison of SS18-SSX2-induced tumors with and with genetic stabilization of β-catenin.

A. Radiograph, gross and cross sectional photographs each with light and GFP fluorescence demonstrate the typical tumor that has developed by 8 weeks after TATCre injection into Rosa26^hSS2/_wt; Ctnnb1^ex3fl/_wt mice at age 4 weeks. B. Kaplan-Meier plot of the relative latency to tumorigenesis following TATCre injection at age 4 weeks into Rosa26^hSS2/_wt mice with (n = 16) or without (n = 19) an ex3f l allele of Ctnnb1. C. Westerns of cytoplasmic (cyt.) and nuclear (nuc.) protein fractions from tumors demonstrate degradation to below detectable levels of full length β-catenin in tumors heterozygous for the stabilized, Δex3 form, suggesting feedback activation. D. Comparison of radiographic evidence of skeletal element invasion, muscle invasion by monophasic areas of tumor cells, the maximal epithelial differentiation, and immunophenotype of both monophasic and biphasic areas of TATCre-induced Rosa26^hSS2/_wt tumors with or without stabilized β-catenin. (Magnification bars are 50 μm. Immunohistochemistry photomicrographs are 50 μm-square panels. Open arrows indicate epithelial glands. Filled arrows indicate swirls of mesenchymal appearing cells, the structure most similar to glands that formed in tumors with stabilized β-catenin. * indicates position of vessel.)