PIN4

PIN‑4 is a triple IHC antibody cocktail composed of p63, a high molecular‑weight cytokeratin (34βE12) and AMACR/P504S, designed to aid in distinguishing prostatic adenocarcinoma from benign lesions. Malignant glands lack basal cells (therefore show loss of p63 and HMWCK staining) while often demonstrating increased cytoplasmic AMACR expression, whereas benign glands retain basal cell markers and typically lack AMACR staining. This combined staining pattern makes PIN‑4 particularly useful in evaluating small foci of atypical glands and in resolving challenging prostate needle biopsy interpretations (1).

Recommended Controls

The criteria for acceptable staining is nuclear (p63), cytoplasmic (high molecular weight cytokeratin) and granular cytoplasmic (AMACR/P504S). The recommended negative controls to use include testes, tonsil or appendix. For the positive control, normal prostate including prostate cancer should show positive staining in the normal prostatic epithelium as well as in the tumour cells.

Expected staining pattern

Prostate cancer including normal prostate (1)

Prostate cancer including normal prostate (2)

Disclaimer

These methods are intended as a guide only. Laboratories that wish to implement these methods should perform internal validation/verification prior to use. The RCPAQAP does not make any claim or warranty for the accuracy or performance of these methods.