Immunohistochemistry in the diagnosis of minimal prostate cancer

SummaryThe diagnosis of minimal prostatic adenocarcinoma can be challenging in prostate needle biopsy tissues, and immunohistochemistry may be needed to substantiate the diagnosis of prostatic adenocarcinoma and/or exclude one of its benign mimickers. Basal cell markers, such as those targeted by the 34βE12 antibody, and antibodies directed against cytokeratin (CK) 5/6 or p63, are very useful for demonstrating basal cells as their presence argues against a diagnosis of invasive carcinoma. The detection of α-methylacyl-coenzyme-A racemase in the appropriate histological context, and with the concurrent use of basal cell markers, can be very useful in confirming an impression of adenocarcinoma. It is important to be aware of the different caveats associated with the use of these markers. Cutting and saving interval sections and performing immunohistochemistry on destained haematoxylin and eosin-stained sections are methods that can be used to increase the diagnostic yield of immunohistochemistry in the assessment of prostatic lesions.