AMACR Detection in Urine Samples. Lack of Clinical Application in Routine Practice

ABSTRACT

PSA is still recognized as the best marker available for detection and treatment monitoring of prostate cancer. However limitations of PSA testing raise a need for other valuable cancer markers. Expression of AMACR protein is recognized as a potential predictive marker, highly competitive to the PSA. Based on preliminary study on AMACR urine detection, the urine without prior prostate manipulations was tested for AMACR detection and radiotherapy treatment monitoring of prostate cancer. Urine samples derived from 57 patients were analyzed. Mainly, there were prostate cancer patients - 43 cases, benign prostate disease - 4 cases and lung (7 cases) as well as urinary bladder (3 cases) cancer patients. Samples were examined for AMACR and PAP staining using Western blot. In none of the prostate cancer patients AMACR protein was identified. However in 1/3 of urine samples of bladder cancer patients AMACR protein was detected. PAP staining performed on the same samples was positive in all prostate but not in other cancer (lung, bladder) cases. Testing of the urine without prior prostate manipulations (massage, USG, biopsy) is the most probable reason for the Western blot AMACR negative results. On the other hand positive AMACR staining in bladder cancer raise the possibility of false positive results. Therefore urine AMACR testing in prostate cancer cannot be recommended.