AR (CAG)_n Microsatellite and APEX1 c.444T>G (p.Asp148Glu) Polymorphisms as Independent Prognostic Biomarkers in Prostate Cancer: Insights from an Argentinian Cohort

Background/Objectives: Prostate cancer (PCa) is the leading malignancy and the third most common cause of cancer-related death in Argentinian men. Predicting outcomes in localized PCa remains difficult due to tumor heterogeneity. In this study, we assessed the impact of AR (CAG)_n and APEX1 c.444T>G polymorphisms on biochemical relapse in Argentine patients with localized PCa. Methods: We genotyped blood samples from 123 PCa patients for AR (CAG)_n and APEX1 p.Asp148Glu (c.444T>G) polymorphisms. Associations with clinicopathological parameters and biochemical relapse-free survival (BRFS) were assessed. Results: AR (CAG)_20–23 was associated with a family history of breast/ovarian cancer (p = 0.0469). The combination of AR (CAG)_20–23 and APEX1 c.444TT/GG correlated with a 2.89 times higher risk of biochemical relapse (log-rank p = 0.006). Multivariable analysis confirmed AR and APEX1 polymorphisms as independent predictors of biochemical relapse (HR = 3.95, p = 0.002). In patients with PSA levels <10 ng/mL, combined AR (CAG)_20–23 and APEX1 c.444TT/GG genotypes were significantly associated with an increased risk of biochemical relapse (HR = 2.61, p = 0.044). Multivariable analysis confirmed the prognostic significance of these genotypes (HR = 3.44, p = 0.02). Conclusions: This study has identified AR (CAG)_n and APEX1 c.444T>G polymorphisms as independent predictors of PCa relapse in Argentinian patients, suggesting their potential use in improving prognostic models.