PTEN and prostate cancer: Prostate-specific ablation of loxP-flanked Pten gene (Ptenfx/fx) utilizing different Cre transgenic mice lines such as probasin-Cre, prostate-specific antigen (PSA)-Cre or mouse mammary tumor virus (MMTV)-Cre has shown the occurrence of prostate cancer progression similar to that which occurs in humans [20], [21], [22], [23].