Glutathione S-transferase Pi-1 gene methylation in early detection of prostate cancer in Egyptian patients

Aim. This study has assessed the role of Glutathione S-transferase Pi 1 gene (GSTP1) methylation among Egyptian patients with prostate cancer and its potential use through urinary sample analysis as a sensitive non-invasive molecular technique for early detection of prostate cancer. Methods. The study was conducted on fifty age-matched Egyptian males. Twenty three of them were undergone TRUS-guided biopsy of the prostate for suspected malignancy. The remaining were divided into 17 individuals with PSA level between 3-10 ng/mL, and 10 healthy controls with PSA values less than 2 ng/mL. DNA was extracted from urine samples, peripheral blood leukocytes, and paraffin-embedded tissue sections. Methylation specific PCR was done for detection of GSTP1 hypermethylation. Results. According to biopsy results; 11 out of 23 patients proved to have prostatic carcinoma, 10 patients with benign prostatic hyperplasia (BPH), and 2 patients with prostatic intraepithelial neoplasia (PIN). Positive GSTP1 methylation pattern was detected in 90.9% (10/11) of DNA extracted from both tissue and urine of patients with prostatic carcinoma, 16.7% of patients with BPH showed positive GSTP1 methylation pattern. 64.7% (11/17) of subjects with serum PSA levels between 3.0-10.0 ng/mL have shown positive GSTP1 methylation pattern. GSTP1 methylation was detected in 40% (4/10) of control individuals. Conclusion. Among the Egyptian patients, GSTP1 methylation could be used as a reliable molecular biomarker (90.9% sensitivity, 60% specificity) for early detection of prostate cancer as confirmed by TNM staging. It is non-invasive and sensitive molecular biomarker to detect prostate cancer using urine samples.