Role of glutathione-S-transferase gene P1 in the diagnosis of prostate cancer in patients with 'grey level' prostate-specific antigen values

Prostate cancer (PC) represents the second most frequent cancer diagnosis in men and, at the same time, is one of the top six causes of death worldwide. The aim of the present study was to evaluate the diagnostic value of glutathione-S-transferase gene P1 (GST-P1) in patients that fall within the 'grey area' of the prostate-specific antigen (PSA) values. A retrospective observational study on 80 patients with prostate abnormal volumes and PSA values in the range 4-10 ng/ml was performed. The prostate gland was extracted following transrectal ultrasonography, and GST-P1 gene expression was analysed. A histopathological examination was considered the gold standard for PC diagnosis. Among the 53 patients diagnosed with PC, 69.8% (n=37) were GST-P1-positive, whereas, among the 27 patients diagnosed with benign prostatic hyperplasia, 18.5% (n=5) were GST-P1-positive. The sensitivity for diagnosing PC in patients with PSA values between 4 and 10 ng/ml was 69.81%, and the specificity was 81.48%. The positive predictive value was 88.1% [95% confidence interval (CI), 74.37-96.02%] and the negative predictive value was 57.89% (95% CI, 40.82-73.69%). Collectively, these results show the potential of using GST-P1 gene expression in patients who are suspected of having PC, but where the PSA values are inconclusive.