TGFB1 and neoplasm: In mouse models, tumors developed from tissues with deletion or inactivation of TβR exhibit increased cell proliferation and decreased cell apoptosis, accompanied by reduction in p15, p21, and p27, the elevation of MYC, cyclin D1, and epidermal growth factor receptor (EGFR), as well as activation of STAT3 and PI3K/AKT pathways.761–765 Interestingly, reconstituted expression of TβRII in tumor cells with corresponding deficiency not only restores the inhibitory responses to TGF-β but also significantly attenuates the tumorigenicity of these cells.824