Immunohistochemistry

 

AMACR (“racemase”, antibody name p504s) is a tumor marker that is usually positive in prostate cancer and usually negative in benign glands. To be considered positive the stain must have a distinct coarse granularity, typically with accentuation along the luminal border. A weak positivity does not count.

 

Use AMACR with caution. Do not over-interpret the results! Some cancers may be negative and a weakly or even moderately positive stain may be seen in benign lesions or even in normal glands.

 

Cancer positive for AMACR. Benign glands (to the right) negative.