[Detection of P504S (alpha-methylacyl-CoA racemase) in prostatic adenocarcinomas]

Abstract

Objective: To evaluate the specificity and sensitivity of the monoclonal antibody P504S (AMACR) in detection of prostatic adenocarcinomas.

Methods: 150 cases, including prostatic adenocarcinomas (n = 105), benign prostatic hyperplasia (BPH, n = 42) and atypical small acinar proliferation (ASAP, n = 3), were studied by immunohistiochemical analysis of P504S. The clinical data, HE, PSA and CK34betaE12 staining slides were reviewed in all of the cases.

Results: P504S was strongly and diffusely positive (> or = +++) in 97.1% cases of prostatic adenocarcinomas and focally positive (+) in 2 cases, regardless of Gleason score, age and serum PSA. However, P504S was also positive in high grade PIN that surrounded adenocarcinomas (n = 24) and weakly positive (+) in benign prostatic hyperplasia that surrounded adenocarcinomas (8 out of 82 cases). In 42 cases of BPH, 10 cases (23.8%) show (+) staining, and 1 case (2.4%) shows (++) staining. P504S was negative in entire 8 cases of basal cell hyperplasia (BCH) and in 3 cases of ASAP.

Conclusion: P504S (AMACR), a recently established positive marker for prostatic adenocarcinomas, has good sensitivity (97.1%) and specificity (86.0%). It is crucial to correlate the P504S staining pattern with the findings of HE, PSA and CK34betaE12 (or p63) staining, as well as clinical information to reach a correct diagnosis.