Purpose: Lowered thiol (-SH) groups and glutathione (GSH) metabolism may be associated with prostate cancer (PCa) and benign prostatic hyperplasia (BPH). The objectives of this study were to systematically review and meta-analyze the associations among -SH groups, GSH, GSH peroxidase (GPx), GSH reductase (GR), and GSH transferase (GST) and PCa/BPH.
Methods: Four electronic databases were searched for studies that reported -SH and GSH variables in PCa/BPH and healthy controls (HC) and the data were meta-analyzed by calculating Hedges's g with 95% confidence intervals.
Results: Twenty studies were included in this meta-analysis. Total -SH (g = -1.750, -2.341/-1.159), GPx (g = -0.789, -1.234/-0.344), GSH (g = -2.219, -4.132/-0.305), and the combination of -SH, GPx, and GSH (g = -1.271, -1.271/-0.800) were significantly lower in PCa patients than in HC. -SH (g = -1.752, -3.123/-0.381) and the combination of -SH, GPx, and GSH (g = -0.813, -1.298/-0.327) were significantly lower in BPH patients than in HC. GPx was significantly lower in PCa than in BPH patients (g = -0.455, -0.896/-0.014). Heterogeneity levels were very high, but Egger's test showed that none of the biomarkers showed significant publication bias.
Conclusion: Thiol/GPx antioxidant defenses are significantly attenuated in patients with PCa while patients with BPH occupy an intermediate risk group position between PCa patients and HC.
Keywords: Antioxidants; benign prostatic hyperplasia; biomarkers; oxidative stress; prostate cancer.