Can the expression level of PIWIL 2 gene be a serum marker for prostate cancer? A single-center prospective study.

OBJECTIVE: The aim of the present study was to evaluate the predictive value of the serum expression level of Piwi-like 2 (PIWIL2), a stem cell protein, for prostate cancer (PCa).

MATERIALS AND METHOD: This randomized and prospective study included a total of 60 volunteers between 50 and 75 years old. Cases were assigned to three groups according to prostate-specific antigen (PSA) elevations and pathology reports, with 20 participants in each group. The first group included patients with a PSA level of >4 ng/dL and with PCa, the second group included patients with a PSA level of >4 ng/dL and with benign prostate hyperplasia, and the third group included patients with a PSA level of ≤4 ng/dL and with benign prostate hyperplasia. The levels of serum PSA and PIWIL2 expressions were compared between the groups.

RESULTS: The median serum PSA levels were 28.5 (4.6-98.1) ng/mL, 8.89 (4.3-24.1) ng/mL, and 2.4 (0.3-3.8) ng/mL for groups 1, 2, and 3, respectively. The PSA levels were significantly different between the groups (p<0.001). The median PIWIL2 gene expression levels were 2.54 (0.28-9.27), 2.27 (0.6-9.38), and 1.17 (0.26-3.07) for groups 1, 2, and 3, respectively. The PIWIL2 gene expression level was found to be lower in patients with a PSA level of <4 (p=0.02). No significant difference was observed between patients with and without cancer among those with a PSA level of ≥4 (p>0.05). Patients diagnosed with cancer were grouped according to the criteria of the International Society of Urological Pathology (ISUP), and PIWIL2 gene expression was observed to be significantly higher among patients with ISUP of >3 than among those with ISUP of ≤3 (p=0.04).

CONCLUSION: In our study, it was observed that the serum level of PIWIL2 gene expression could not be a diagnostic indicator of PCa; however, it could be a beneficial prognostic indicator particularly for progressed disease.