Background: The Prostatic cancer antigen 3 (PCA3) is extensively over-expressed in the malignant prostatic tissues more than normal or benign adjacent ones. Clinical diagnosis and targeted therapy are two areas where this biomarker shows a promising value. The present work aimed to evaluate the role of serum and urinary PCA3 as a diagnostic marker in prostatic cancer cases in Zagazig University Hospitals.

Subjects and methods: In a case-control study, we included 44 patients who were divided into two groups: 22 patients with benign prostatic hyperplasia as a control group and 22 patients with prostate cancer. Cases were subjected to full history taking, clinical evaluation, and determination of total Prostate-specific antigen (PSA), free PSA, serum, and urinary PCA3.

Results: Both serum and urinary PCA3 were significantly higher in the cancer group than in the control group (P=0.007 and P<0.001, respectively). The best cutoff of serum PCA3 to diagnose prostate cancer is ≥5.985pg/ml with the area under curve 0.739, sensitivity 86.3%, specificity 54.5%, positive predictive value 65.5%, negative predictive value 80%, and overall accuracy 70.5% (p=0.007). The best cutoff of urinary PCA3 to diagnose cancer prostate is ≥9.775pg/ml with area under curve 0.965, sensitivity 95.5%, specificity 95.5%, positive predictive value 95.5%, negative predictive value 95.5% and overall accuracy 95.5% (p<0.001).

Conclusion: When compared to PSA, urinary PCA3 had the better diagnostic specificity and sensitivity, making it a promising biomarker and noninvasive test for prostate cancer diagnosis. It could be used in diagnosis of PCA either alone or in combination with total PSA