PSAP or Prostatic acid phosphatase is the glandular epithelium of normal, hyperplastic prosate and prosate carcinoma. PSAP similar to PSA can be used to identify tumours origin, whether it originated in the prostate. The staining is more sensitive but is less specific than PSA.

The staining pattern of PSAP is Cytoplasmic as shown below.

Picture 1 – PSAP positivity in Prostate

 

PSAP has several different applications. Below are a few examples.

Tumour or cell type	PSAP + or -
Prostate Tissue	Positive
Prostate Carcinoma	Positive
Lung Carcinoma	Negative
Breast carcinoma	Negative