Some established animal models include tumor suppressor knockout PTEN mouse (Wang et al., 2003); gain of function model such as the c-myc mouse (Ellwood-Yen et al., 2003); and various conditional knockouts of multiple genes including the NKX3.1 (Kim et al., 2002); p27/Kip1 knockout (Gao et al., 2004) and the p53 and retinoblastoma (Rb) double knockout mouse (Zhou et al., 2006), which correlate with possible similar alterations in human prostate cancer. Here, CDKN1B is linked to prostate cancer.