To gain in vivo insights into the cellular mechanisms involved in metastasis and to investigate the role of Plexin-B1 in this process, we genetically manipulated the expression of WT and mutant (P1597L) Plexin-B1 in two models of prostate cancer and studied the effect on prostate cancer progression in vivo. This evidence concerns the gene PLXNB1 and Familial prostate cancer.