SMAD4 and posterior cortical atrophy: To extend these observations, we employed synergistic models including Myc-CaP and Pten; Trp53; Smad4 triple KO (TKO) cells derived from a c-Myc transgenic mouse or ProbasinCre/+; PtenPC−/−; Trp53flox/flox; Smad4flox/flox mouse with PCa.