Immunohistochemistry in prostate neoplasia: pitfalls and progress

Prostatic immunohistochemistry is commonly used to either distinguish prostatic adenocarcinoma from benign prostate glands or to establish the prostatic lineage of a poorly differentiated carcinoma. Awareness of the many potential pitfalls in prostatic immunohistochemistry is essential to avoid serious misdiagnosis. Histopathologists must be particularly aware of the pitfalls in the interpretation of immunostained sections (identifying immunostaining as positive or negative) and in the interpretation of the immunoprofile of a tumour. This review describes pitfalls at the pre-analytic, analytic and post-analytic stages of testing with a particular focus on the pitfalls in the interpretation stage together with advice on steps that must be taken to avoid these pitfalls. The importance as well as the limitations of using external and internal tissue controls in prostatic immunohistochemistry are presented. Recent advances in prostatic immunohistochemistry are also briefly outlined.