Introduction: Current prostate cancer screening relies on the PSA test and the digital rectum rectal examination (DRE), which have relatively low specificity. A more specific marker is in need for prostate cancer screening and risk stratification could reduce the burden of unnecessary biopsies. AMACR, has been proven to be an excellent tissue marker for prostate caner, could be an attractive candidate, but. Soso far, serum the detection of AMACR detection in serum has been unsuccessfuldifficult. This study explored the detection of AMACR protein in semen ejaculate and its potential as a non-invasive test in the diagnosis and management of prostate cancer.

Methods: Semen ejaculates were analyzed from 23 prostate cancer (biopsy proven) patients, 21 of which had prostatectomy, as well as 15 age-comparable controls (>50y, PSA<2 ng/mL, assumed prostate cancer free). An indirect sandwich ELISA chemiluminescence assay was used to test semen AMACR protein. Tissue AMACR protein was also quantified in 13 corresponding prostatectomy specimens using automated quantitative analysis (AQUATM).

Results: AMACR was detected in 19 of 23 (83%) semen ejaculates of prostate cancer patients. Among the other 4 patients with undetectable semen AMACR, one had no residual tumor in the prostatectomy specimen (#40), one had Gleason score of 9 cancer (#37) with no detectable tissue AMACR either, while the other two remaining patients (#31 and #33) had a very small volume of cancer on two separate sextant biopsies biopsy sets and are on watchful waiting list. AMACR was also detected in 7 of 15 (47%) control group. Using 100 ng/mL as a cutoff value, semen AMACR protein was positive in 16 of 23 (70%) cancer patients who had underwent prostatectomy and in 5 of 15 (33%) age-comparable controls.

Conclusions: This has been the first study first to demonstrated that AMACR protein is detectable in semen ejaculate. A high semen AMACR detection rate in cancer patients suggested suggests that semen AMACR may be useful, supplemental, as a non-invasive test in addition toto the PSA test for detecting prostate cancer, especially cancer of significant volume. Questions regarding specificity of AMACR are, however, raised. Given the lack of prostate biopsy confirmation, The the age-comparable controls in this study may not be an entirely representative sample of men free of prostate cancer without confirmation by prostate biopsy. This Our study's findings will form the basis for the design of a larger finding need to be further validated in a larger prospective screening trial of AMACR.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4630.