α-Methylacyl Coenzyme A Racemase as a Tissue Biomarker for Prostate Cancer

To determine the expression and clinical utility of alpha-methylacyl coenzyme A racemase (AMACR), a gene identified as being overexpressed in prostate cancer by global profiling strategies.

Four gene expression data sets from independent DNA microarray analyses were examined to identify genes expressed in prostate cancer (n = 128 specimens). A lead candidate gene, AMACR, was validated at the transcript level by reverse transcriptase polymerase chain reaction (RT-PCR) and at the protein level by immunoblot and immunohistochemical analysis. AMACR levels were examined using prostate cancer tissue microarrays in 342 samples representing different stages of prostate cancer progression. Protein expression was characterized as negative (score = 1), weak (2), moderate (3), or strong (4). Clinical utility of AMACR was evaluated using 94 prostate needle biopsy specimens. MAIN OUTCOME MEASURES: Messenger RNA transcript and protein levels of AMACR; sensitivity and specificity of AMACR as a tissue biomarker for prostate cancer in needle biopsy specimens.