High PBX3 expression was closely associated with slower progression to castration‐resistant PCa (SHR 0.18, 95% CI: 0.081–0.42, p values <0.001). PBX3 expression combined with Gleason score and age showed a high predictive accuracy (AUC = 0.82). Patients undergoing radical prostatectomy, with high expression of PBX3 showed improved prostate cancer specific survival compared to patients expressing low levels (SHR 0.21, 95% CI: 0.46–0.93, p values < 0.001 and AUC = 0.75). The gene discussed is PBX3; the disease is Familial prostate cancer.