• All IHC stains will include a positive control tissue

PSAP is fairly specific for prostate tissue

• Immunoreactivity for PSAP (and PSA) is generally more intense and homogeneous in benign prostate tissue than in prostatic carcinoma. Occasional cases of prostatic squamous metaplasia may show focal reactivity
• Other normal/non-neoplastic tissues with reported PSAP reactivity:
  - periurethral glands*
  - anal glands (male only)*
  - urachal remnants*
  - renal tubules
  - neutrophils (cross reactivity with leukocyte acid phosphatase)
  - pancreatic islet cells
  - neuroendocrine cells in clonic crypts
  - seminal vesicle**
  - cystitis cystica and glandularis*
  - (rare reports of focal PSAP reactivity in hepatocytes, breast ducts, and gastric parietal cells)
• Other neoplasms with reported PSAP reactivity:
  - pure adenocarcinoma of the bladder*
  - periurethral gland carcinomas*
  - gastrointestinal carcinoids (approx. 70% of rectal carcinoids; the frequency of PAP positivity decreases as one ascends the gastrointestinal tract)
  - pancreatic islet cell tumors
  - (rare reports of PSAP reactivity in renal cell carcinoma and breast carcinoma)
• In general, any cloacal derived tissue may show reactivity with PSAP
• Normal and neoplastic transitional epithelium is negative

Carcinoids found within the ovary, kidney, breast, liver, and head and neck have been PSAP negative

*both PSAP and PSA reactivity are reported
**reported for antibodies developed against seminal fluid.

Note:

PSAP monoclonal antibodies have shown a lower sensitivity compared to polyclonal antiserum (In two studies of poorly differentiated prostate carcinoma, monoclonal antibodies stained 59% and 60% of cases whereas polyclonal antibodies stained 83% and 86% of cases).