The development of more specific
biomarkers for
prostate cancer and/or high-risk
prostate cancer is necessary, because the
prostate-specific antigen test lacks specificity for the detection of
prostate cancer and can lead to unnecessary prostate biopsies. Urine is a promising source for the development of new
biomarkers of
prostate cancer.
Biomarkers derived from
prostate cancer cells are released into prostatic fluids and then into urine. Urine after manipulation of the prostate is enriched with
prostate cancer biomarkers, which include
prostate cancer cells, DNAs, RNAs,
proteins and other small molecules. The urinary
prostate cancer antigen 3 test is the first Food and Drug Administration-approved
RNA-based urinary marker, and it helps in the detection of
prostate cancer on repeat biopsy. The SelectMDx test is based on
messenger RNA detection of DLX1 and HOXC6 in urine after prostate
massage, and helps in the detection of high-risk
prostate cancer on prostate biopsy. Exosomes are extracellular vesicles with a diameter of 30-200 nm that are secreted from various types of cells. Urinary
prostate cancer-derived exosomes also contain RNAs and
proteins specific for
prostate cancer (e.g. PCA3 and TMPRSS2-ERG), and could be promising sources of novel
biomarker discovery. The ExoDx Prostate test is a commercially available test based on the detection of three genes (PCA3, ERG and SPDEF) in urinary exosomes. Advancement of comprehensive analysis (microarray, mass spectrometry and next-generation sequencing) has resulted in the discovery of several urinary
biomarkers. Non-invasive urinary markers can help in the decision to carry out prostate biopsy or in the design of a therapeutic strategy.