Lower thiol, glutathione, and glutathione peroxidase levels in prostate cancer: a meta-analysis study.

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. 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. 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. 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. [ABSTRACT FROM AUTHOR]