Editing Prostate-specific antigen (section)

===Inactive PSA===

The PSA test in 1994 failed to differentiate between prostate cancer and benign prostate hyperplasia (BPH) and the commercial assay kits for PSA did not provide correct PSA values.<ref name="Wu-1994">{{cite journal | vauthors = Wu JT | title = Assay for prostate specific antigen (PSA): problems and possible solutions | journal = Journal of Clinical Laboratory Analysis | volume = 8 | issue = 1 | pages = 51–62 | year = 1994 | pmid = 7513021 | doi = 10.1002/jcla.1860080110 | s2cid = 13179006 }}</ref> Thus with the introduction of the ratio of free-to-total PSA, the reliability of the test has improved. Measuring the activity of the enzyme could add to the ratio of free-to-total PSA and further improve the diagnostic value of test.<ref>{{cite web | url = http://www.sbir.gov/sbirsearch/detail/12931 |title=A bioelectronic assay for PSA activity }}</ref> Proteolytically active PSA has been shown to have an anti-angiogenic effect <ref name="Mattsson-2008">{{cite journal | vauthors = Mattsson JM, Valmu L, Laakkonen P, Stenman UH, Koistinen H | title = Structural characterization and anti-angiogenic properties of prostate-specific antigen isoforms in seminal fluid | journal = The Prostate | volume = 68 | issue = 9 | pages = 945–954 | date = June 2008 | pmid = 18386289 | doi = 10.1002/pros.20751 | s2cid = 30095129 }}</ref> and certain inactive subforms may be associated with prostate cancer, as shown by MAb 5D3D11, an antibody able to detect forms abundantly represented in sera from cancer patients.<ref name="Stura-2011">{{cite journal | vauthors = Stura EA, Muller BH, Bossus M, Michel S, Jolivet-Reynaud C, Ducancel F | title = Crystal structure of human prostate-specific antigen in a sandwich antibody complex | journal = Journal of Molecular Biology | volume = 414 | issue = 4 | pages = 530–544 | date = December 2011 | pmid = 22037582 | doi = 10.1016/j.jmb.2011.10.007 }}</ref>
The presence of inactive proenzyme forms of PSA is another potential indicator of disease.<ref name="Mikolajczyk-2004">{{cite journal | vauthors = Mikolajczyk SD, Catalona WJ, Evans CL, Linton HJ, Millar LS, Marker KM, Katir D, Amirkhan A, Rittenhouse HG | title = Proenzyme forms of prostate-specific antigen in serum improve the detection of prostate cancer | journal = Clinical Chemistry | volume = 50 | issue = 6 | pages = 1017–1025 | date = June 2004 | pmid = 15054080 | doi = 10.1373/clinchem.2003.026823 | doi-access = free }}</ref>