TCF4 and prostate neoplasm: Co-staining for phosphorylated IGF1R and GSK3β, as well as nuclear β-catenin and its downstream targets, TCF4 and Cyclin D1, with transgenic AR staining appeared specifically in prostate tumor cells (Fig. 6c) in comparison to normal prostatic epithelial cells of WT mouse prostate tissues (Fig. 6d), suggesting the regulatory loop of hARtg expression in elevating IGF1 signaling and activating Wnt/β-catenin axis during PIN and tumor development in R26mTmG/hAR:Osr1Cre/+ mice.