A pilot study on the use of serum glyoxalase as a supplemental biomarker to predict malignant cases of the prostate in the PSA range of 4-20 ng/ml

BACKGROUND & OBJECTIVES Serum prostate specific antigen (PSA) though most commonly used for diagnosis of prostate cancer lacks specificity. This study was aimed at exploring the use of serum glyoxalase as a supplemental biomarker to differentiate between malignant vs non-malignant diseases of the prostate in patients with PSA in the range of 4-20 ng/ml. METHODS Serum glyoxalase and PSA were measured in 92 men (30 control, 31 cases of benign prostate hyperplasia (BPH) and 31 cases of adenocarcinoma of prostate). Of the latter group, 11 cases of prostate cancer in the PSA range of 4-20 ng/ml were included for studying the diagnostic utility of combination of both serum PSA and glyoxalase. RESULTS In prostate cancer cases with PSA in the range of 4-20 ng/ml, the glyoxalase was found to be 233.3 ± 98.6 μmol/min while for the non-malignant group it was 103.1 ± 19.7 μmol/min. A cut-off of 19.2 ng/ml PSA showed sensitivity of 9 per cent, specificity of 96.7 per cent, positive predictive value (PPV) of 50 per cent and negative predictive value (NPV) of 75 per cent. A serum glyoxalase cut-off of 141 μmol/min showed sensitivity of 81.8 per cent, specificity of 100 per cent, PPV of 100 per cent and NPV of 93.9 per cent. Further, ROC analysis showed a significant difference in the area under curve (AUC) for glyoxalase as compared to serum PSA (0.92 vs 0.57; P<0.001). INTERPRETATION & CONCLUSIONS Serum glyoxalase appears to be predictive of prostate cancer in the PSA range of 4-20 ng/ml. Studies with larger number of participants would be required to confirm this finding.