Prostein + PSA + NKX3.1

SKU: 3166 Categories: , , Tags: , ,

The prostein gene encodes a 553-amino acid type IIIa plasma membrane protein with a cleavable signal peptide and 11 transmembrane-spanning regions (1). IHC analysis has demonstrated that the Prostein antibody (also known as P501S) was expressed in the normal prostate tissue and the vast majority of malignant prostatic tissues, regardless of grade and metastatic status (2). Prostein expression was not detected in thousands of representative normal and malignant non-prostatic tissue samples (2). Prostein has a perinuclear-like staining pattern, as expression is found in the Golgi complex of prostate cells. Compared to the PSA antibody, prostein was positive in 99% of metastatic prostate adenocarcinomas while 97% of cases were positive for PSA. No tumor was negative for both markers (3).

Prostate specific antigen (PSA) is a chymotrypsin-like serine protease (kallikrein family) produced by the prostate epithelium. Studies have shown that PSA is highly specific and is used to confirm prostatic acinar cell origin in primary and metastatic carcinomas, and to rule out non-prostatic carcinoma mimics (4-5).

NKX3.1 is a nuclear protein encoded by the NKX3-1 gene located on chromosome 8p. NKX3.1 protein has been found to be expressed in the vast majority of primary prostatic adenocarcinomas with 99.7% specificity. Contrary to earlier studies, NKX3.1 positive staining has now been shown to be highly sensitive and specific for high-grade prostatic adenocarcinomas vs. high-grade urothelial carcinomas. In addition, the sensitivity for identifying metastatic prostatic adenocarcinomas overall was 98.6% (68/69) for NKX3.1 and 94.2% (65/69) for PSA (6).

The International Society of Urological Pathology suggests the use of Prostein and NKX3.1 in addition to PSA, p63 and CK HMW as prostate markers (7). The CK HMW with p63 and AMACR are useful for atypical glands suspicious for adenocarcinoma of the prostate. GATA3 may be used along with PSA to differentially diagnose urothelial carcinoma (7).

Each antibody in this triple antibody cocktail can be morphologically identified in prostate cancers as PSA is a cytoplasmic stain, Prostein is present in the Golgi apparatus with perinuclear staining and NXK3.1 is a nuclear stain. Simultaneous stains with PSA, Prostein and NKX3.1 may greatly improve the detection rate and identification of a significant majority of prostatic metastases, especially poorly differentiated carcinomas of an unknown primary (7).


Prostein, PSA, NKX3.1


10E3, ER-PR8, N/A



Intended Use



N/A, IgG1/kappa, IgG2a/kappa


NKX3.1 – Nuclear, Prostein – Perinuclear, PSA – Cytoplasmic

Positive Control

Prostate cancer, Normal prostate


Mouse Monoclonal, Rabbit Polyclonal

Species Reactivity



6.0 ml

Download Data Sheet
Download SDS Sheet

Regulatory Notice: Biocare’s IVD-labeled products comply with US-FDA regulation. Other regions may have additional requirements for such labeling, please contact your local distributor.

1. Xu J, et al. Identification and characterization of prostein, a novel prostate-specific protein. Cancer Res. 2001 Feb 15; 61(4):1563-8.

2. Kalos M, et al. Prostein expression is highly restricted to normal and malignant prostate tissues. Prostate. 2004 Aug 1; 60(3):246-56.

3. Sheridan T, 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.

4. Hameed O, Humphrey PA. Immunohistochemistry in diagnostic surgical pathology of the prostate. Semin Diagn Pathol. 2005 Feb; 22(1):88-104.

5. Kunju LP, et al. Prostate-specific antigen, high-molecular-weight cytokeratin (clone 34betaE12), and/or p63: an optimal immunohistochemical panel to distinguish poorly differentiated prostate adenocarcinoma from urothelial carcinoma. Am J Clin Pathol. 2006 May; 125(5):675-81.

6. Gurel B, et al. NKX3.1 as a marker of prostatic origin in metastatic tumors. Am J Surg Pathol. 2010 Aug; 34(8):1097-105.

7. Epstein JI, et al. Best practices recommendations in the application of immunohistochemistry in the prostate: report from the International Society of Urologic Pathology consensus conference. Am J Surg Pathol. 2014 Aug; 38(8):e6-e19.

8. Center for Disease Control Manual. Guide: Safety Management, NO. CDC-22, Atlanta, GA. April 30, 1976 “Decontamination of Laboratory Sink Drains to Remove Azide Salts.”

9. Clinical and Laboratory Standards Institute (CLSI). Protection of Laboratory Workers from Occupationally Acquired Infections; Approved Guideline-Fourth Edition CLSI document M29-A4 Wayne, PA 2014.