PCA3 is a new prostate-specific gene that is highly over-expressed in prostate cancer. Specifically it is a nucleic acid amplification assay detecting  in the urine the expression of PSA RNA as a marker of prostate cells and PCA3 RNA which is selectively expressed in the majority of prostate cancers.

 

It is a another diagnostic test that is used in addition to PSA, transrectal biopsy, ultrasound, age and risk factors. For example, a man who is a high risk of developing prostate cancer either by family history or previous biopsy would be a candidate for PCA3. Generally it is not used as a first line test.