Synonyms: P501S
by Jan Klos
Background
P501S is a 553-amino acid protein, also known as prostein. It is a prostate-specific marker that originally was identified by cDNA library subtraction in conjunction with high-throughput microarray screening of prostate carcinomas. It is localized to the Golgi complex in the cytoplasm of glandular cells of the prostate and is expressed by both benign and neoplastic prostate tissue.
Expression i normal and neoplastic tissues
Reactivity for this antibody is typical for normal glandular cells of the prostate and prostate adenocarcinomas. Neuroendocrine small cell carcinoma of the prostate shows around 20% positivity. Positivity is also described in 11% of infiltrating adenocarcinoma (with diffuse cytoplasmic staining pattern) and adenocarcinoma in situ of urinary bladder. Positive staining has not been reported, in any other normal or malignant tissue examined. Some cases of prostate adenocarcinoma especially in metastatic setting may however be negative.
Staining pattern
Staining pattern is granular paranuclear.
Control tissue
Prostate.
Application
- Confirmation of prostate origin of adenocarcinoma
- Supplementary to PSA (used if PSA staining is negative/non conclusive)
Selected references
- Lane Z1, Hansel DE, Epstein JI. Immunohistochemical expression of prostatic antigens in adenocarcinoma and villous adenoma of the urinary bladder. Am J Surg Pathol. 2008 Sep;32(9):1322-6. doi: 10.1097/PAS.0b013e3181656ca0.
- Nadal R1, Schweizer M1, Kryvenko ON2, et al. Small cell carcinoma of the prostate. Nat Rev Urol. 2014 Apr;11(4):213-9. doi: 10.1038/nrurol.2014.21. Epub 2014 Feb 18.
- Sheridan T1, Herawi M, Epstein JI, et al. The role of P501S and PSA in the diagnosis of metastatic adenocarcinoma of the prostate. Am J Surg Pathol. 2007 Sep;31(9):1351-5.