Prostein (P501S) is a 553-amino acid protein. It is a prostate-specific marker originally identified by cDNA library subtraction in conjunction with high-throughput microarray screening of prostate carcinomas. Prostein is localized to the Golgi complex in the cytoplasm of cells and has not been detected in any other normal tissue.
Prostein is detected in almost all prostate carcinomas. Apart from a few urothelial carcinomas prostein has not been detected in any other tumour type.
In the identification of metastatic prostate adenocarcinoma Prostein is as sensitive as Prostate specific antigen (PSA) and slightly more specific. As both can fail when staining low differentied prostatic carcinomas, the two Abs should be used in a panel and/or the nuclear marker NKX3.1 should be included.
Normal prostate is recommended as positive control: The glandular epithelial cells must show an intense granular cytoplasmic reaction, while all other cells should be negative.
Chuang A-Y, DeMarzo AM, Veltri RW, Sharma RB, Bieberich CJ, Epstein JI. Immunohistochemical differentiation of high-grade prostate carcinoma from urothelial carcinoma. Am J Surg Pathol 2007;31(8):1246-55 Kalos M, Askaa J, Hylander BS, Repasky EA, Cai F, Vedvick T, Reed SG, Wright GL Jr, Fanger Prostein expression is highly restricted to normal and malignant prostate tissues. The Prostate 2004; 60:246 Xu J, Kalos M, Stolk JA, Zasloff EJ, Zhang X, Houghton RL, Filho AM, Nolasco M, Badaro R, Reed SG. Identification and characterization of prostein, a novel prostate-specific protein. Cancer Res. 2001; 61:1563