PSA

PSA (Prostate‑Specific Antigen) is an androgen‑regulated serine protease and a highly sensitive and specific cytoplasmic IHC marker for prostatic epithelium and prostatic adenocarcinoma, making it a key in confirming tumours of prostatic origin. Normal prostate acinar and ductal secretory cells show strong cytoplasmic staining, whereas most non‑prostatic tissues and benign lesions are negative. Loss or reduction of PSA expression may occur in poorly differentiated or high‑grade prostate cancers, but the marker remains positive in the vast majority of prostatic adenocarcinomas, including many metastatic deposits(1).

Recommended Controls

The criteria for acceptable staining is a cytoplasmic staining pattern. 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. The testes, tonsil and appendix will be negative.

Expected staining pattern

Prostate

Tonsil

Appendix

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.