Urinary Prostate Cancer Antigen 3 as a Tumour Marker: Biochemical and Clinical Aspects

Due to low specificity of Prostate-Specific Antigen (PSA) we face a certain risk of overdiagnosis and overtreatment of Prostate Cancer (PCa). The benefits and harms of PSA-screening are controversially discussed. To overcome this weakness of PSA novel PCa biomarkers and detection tools are required.The urine-based biomarker Prostate Cancer Antigen 3 (PCA3) has been shown to be highly PCa-specific. Application of PCA3 was tested in the diagnostic setting and staging. Several studies pointed out the additional value of PCA3 for further stratification of men selected for biopsy (BX) based on an elevated PSA and/or an abnormal digital rectal examination (DRE). Its combined use with established clinical risk factors for positive prostate BX, particularly within nomograms or risk calculators, may represent a valid and helpful aid for clinicians in patient counselling and BX indication confirmation.When it comes to prediction of favourable or unfavourable histopathological features, respectively, such as tumour volume or PCa significance, PCA3's value remains controversial. Based on relatively small patient numbers, PCA3 has been identified to independently predict small-volume and insignificant PCa. However, in other studies PCA3 was not associated with advanced disease and its ability of predicting PCa aggressiveness in men undergoing radical prostatectomy is limited.PCA3's value may be best given for BX outcome prediction. Finally, the implementation of the PCA3 promoter in developing new highly PCa-specific gene therapies represents a promising perspective in the near future.