| Identity |
| Other names | PRO232 |
| HGNC (Hugo) | PSCA |
| Location | 8q24.3 |
| Location_base_pair | Starts at 143758877 and ends at 143761145 bp from pter ( according to hg18-Mar_2006) [Mapping] |
| DNA/RNA |
| Description | The PSCA gene was originally identified by Reiter el al. (1998) through an analysis of genes up-regulated in the human prostate cancer LAPC-4 xenograft model. The PSCA gene is located on chromosome 8q24.2. |
| Transcription | In normal human tissues, PSCA mRNA expression is found in the prostate, with lower expression in placenta and very low expression in kidney and small intestine (Reiter et al., 1998; Cunha et al., 2006). Within normal human prostate sections, in situ hybridizations by Reiter el al. (1998) demonstrated PSCA mRNA expression in the subjacent basal cells, while Ross et al. (2002) demonstrated PSCA mRNA expression in the secretory luminal cells. These contrasting results may be due to sampling error from relatively small biopsies, since PSCA protein expression was seen in both cell types (see below). |
| Protein |
| Description | The PSCA gene encodes a 123 amino acid cell surface protein with a molecular weight of 10-24 kDa (Reiter et al., 1998). Inaccurately named for its 30% homology to stem cell antigen type 2 (SCA-2), an immature lymphocyte cell surface marker, PSCA is neither a marker for a stem cell population nor is it exclusively expressed in the prostate. Like SCA-2 however, PSCA is a member of the Thy-1/Ly-6 family of glycosylphosphatidylinositol (GPI) anchored surface proteins. |
| Expression | In the human prostate, PSCA protein expression is found in both the basal and secretory epithelial cell layers, along with the neuroendocrine cells. Additionally, PSCA protein expression was demonstrated in the placenta, the bladder, the neuroendocrine cells of the stomach and colon, and weakly in the kidneys excluding the glomeruli (Gu et al., 2000). |
| Localisation | PSCA is localized to the cell surface, anchored by a GPI linkage. |
| Function | Although the function of PSCA is currently unknown, PSCA homologues give some insight into possible functions. It has been previously shown that proteins in the Thy-1 family have been reported to function in T cell activation (Presky et al., 1990) and proliferation, stem cell survival, and cytokine and growth factor response (Rege et al., 2006), while the family of Ly-6 genes has been associated with carcinogenesis (Treister et al., 1998; Witz et al., 2000), cellular activation (Malek et al., 1986) and cell adhesion of tumor cells (Eshel et al., 2000). PSCA does not seem to be critical for normal development or urogenital function since a PSCA knockout mouse created by Moore et al. (2008) was viable, grew to adulthood and had normal litters. Additionally, these PSCA knockout mice did not have an increased incidence of carcinogenesis. |
| Homology | A murine PSCA (mPSCA) homologue was also identified by Reiter et al. (1998) and it is located on chromosome 15. mPSCA has 70% homology to human PSCA at the nucleotide and amino acid levels. |
| Mutations |
| Note | While no mutation is known for PSCA, a recent study by the Study Group of Millennium Genome Project for Cancer (2008) found a significant association between two Single Nucleotide Polymorphisms (SNPs) in the PSCA gene and diffuse-type gastric cancer. |
| Implicated in |
| Entity | Prostate Cancer |
| Note | In human prostate cancer, PSCA over-expression is present in primary human prostate tumors and residual tumors removed after androgen ablation therapy (Reiter et al., 1998; Gu et al., 2000). There is a significant correlation between PSCA expression and seminal vesicle invasion, capsular involvement (Han et al., 2004), Gleason score, tumor stage and progression to androgen-independence (Gu et al., 2000). PSCA expression also correlates with metastasis, with a higher percentage of metastatic tumors expressing PSCA compared to non-metastatic tumors (Ross et al., 2002). In particular, bone marrow metastases show relatively higher intensity of PSCA expression compared to lymph node and liver metastases (Gu et al., 2000; Lam et al., 2005). |
| Prognosis | PSCA has been tested as a prostate cancer biomarker, with limited but interesting results. One study by Hara et al. (2002) screened for the presence of PSCA mRNA in a milliliter of patient blood via reverse transcription-polymerase chain reaction (RT-PCR) but found only 13.8% of prostate cancer cases positive for PSCA mRNA. However, this study also found that stage IV, PSCA mRNA positive patients correlated with a lower disease-free survival compared to stage IV, PSCA mRNA negative patients. In a separate study by Zhigang et al. (2008), 23.7% of men with benign prostatic hyperplasia (BPH) treated with transurethral resection of the prostate (TURP) who were positive for PSCA mRNA expression went on to develop prostate cancer versus only 1.0% of patients who were negative. |
| Oncogenesis | PSCA's role in prostate carcinogenesis remains unknown. The location of the PSCA gene at 8q24.2 has some interesting correlations however. Chromosome 8q is commonly amplified in metastatic and recurrent prostate carcinoma, and this amplification is associated with a poor prognosis (Visakorpi et al., 1995; Sato et al., 1999). Additionally, PSCA expression may be a marker for MYC amplification, a common mutation in prostate cancer, since both genes are located close to one another (Qian et al., 1995; Jenkins et al., 1997; Jalkut et al., 2002). |
| Entity | Additional cancers |
| Note | In addition to the identification of PSCA as a prostate tumor associated protein, several other tumors have shown associations with PSCA expression including pancreatic adenocarcinoma (Argani et al., 2001; Iacobuzio-Donahue et al., 2002; Wente et al., 2005), transitional cell carcinoma (Amara et al., 2001; Elsamman et al., 2006), renal cell carcinoma (Elsamman et al., 2006) and diffuse-type gastric cancer (The Study Group of Millennium Genome Project for Cancer, 2008). |
| To be noted |
| The current role of PSCA as a diagnostic, prognostic and therapeutic tool was recently reviewed by our laboratory (Raff et al., 2008). While the use of PSCA as a target in the treatment of human prostate cancer is not covered here, it represents an ideal choice for immunotherapy due to its overexpression in prostate tumors and limited expression in normal tissues. For example, our laboratory recently demonstrated that PSCA vaccination of TRAMP mice that spontaneously generate prostate cancer conferred a 90% survival rate at 12 months of age in contrast to control mice which had all succumbed to prostate cancer or had heavy tumor loads (Garcia-Hernandez et al., 2008). |
| External links |
| Bibliography |
| Role of Ly-6 in lymphocyte activation. II. Induction of T cell activation by monoclonal anti-Ly-6 antibodies. |
| Malek TR, Ortega G, Chan C, Kroczek RA, Shevach EM. |
| J Exp Med. 1986 Sep 1;164(3):709-22. |
| PMID 3489060 |
| Role of phosphatidylinositol-anchored proteins in T cell activation. |
| Presky DH, Low MG, Shevach EM. |
| J Immunol. 1990 Feb 1;144(3):860-8. |
| PMID 1967276 |
| Chromosomal anomalies in prostatic intraepithelial neoplasia and carcinoma detected by fluorescence in situ hybridization. |
| Qian J, Bostwick DG, Takahashi S, Borell TJ, Herath JF, Lieber MM, Jenkins RB. |
| Cancer Res. 1995 Nov 15;55(22):5408-14. |
| PMID 7585610 |
| Genetic changes in primary and recurrent prostate cancer by comparative genomic hybridization. |
| Visakorpi T, Kallioniemi AH, Syvanen AC, Hyytinen ER, Karhu R, Tammela T, Isola JJ, Kallioniemi OP. |
| Cancer Res. 1995 Jan 15;55(2):342-7. |
| PMID 7529134 |
| Detection of c-myc oncogene amplification and chromosomal anomalies in metastatic prostatic carcinoma by fluorescence in situ hybridization. |
| Jenkins RB, Qian J, Lieber MM, Bostwick DG. |
| Cancer Res. 1997 Feb 1;57(3):524-31. |
| PMID 9012485 |
| Prostate stem cell antigen: a cell surface marker overexpressed in prostate cancer. |
| Reiter RE, Gu Z, Watabe T, Thomas G, Szigeti K, Davis E, Wahl M, Nisitani S, Yamashiro J, Le Beau MM, Loda M, Witte ON. |
| Proc Natl Acad Sci U S A. 1998 Feb 17;95(4):1735-40. |
| PMID 9465086 |
| Expression of Ly-6, a marker for highly malignant murine tumor cells, is regulated by growth conditions and stress. |
| Treister A, Sagi-Assif O, Meer M, Smorodinsky NI, Anavi R, Golan I, Meshel T, Kahana O, Eshel R, Katz BZ, Shevach E, Witz IP. |
| Int J Cancer. 1998 Jul 17;77(2):306-13. |
| PMID 9650569 |
| Clinical significance of alterations of chromosome 8 in high-grade, advanced, nonmetastatic prostate carcinoma. |
| Sato K, Qian J, Slezak JM, Lieber MM, Bostwick DG, Bergstralh EJ, Jenkins RB. |
| J Natl Cancer Inst. 1999 Sep 15;91(18):1574-80. |
| PMID 10491435 |
| The GPI-linked Ly-6 antigen E48 regulates expression levels of the FX enzyme and of E-selectin ligands on head and neck squamous carcinoma cells. |
| Eshel R, Zanin A, Sagi-Assif O, Meshel T, Smorodinsky NI, Dwir O, Alon R, Brakenhoff R, van Dongen G, Witz IP. |
| J Biol Chem. 2000 Apr 28;275(17):12833-40. |
| PMID 10777581 |
| Prostate stem cell antigen (PSCA) expression increases with high gleason score, advanced stage and bone metastasis in prostate cancer. |
| Gu Z, Thomas G, Yamashiro J, Shintaku IP, Dorey F, Raitano A, Witte ON, Said JW, Loda M, Reiter RE. |
| Oncogene. 2000 Mar 2;19(10):1288-96. |
| PMID 10713670 |
| Differential expression of genes by tumor cells of a low or a high malignancy phenotype: the case of murine and human Ly-6 proteins. |
| Witz IP. |
| J Cell Biochem Suppl. 2000;34:61-6. (REVIEW) |
| PMID 10762016 |
| Prostate stem cell antigen is overexpressed in human transitional cell carcinoma. |
| Amara N, Palapattu GS, Schrage M, Gu Z, Thomas GV, Dorey F, Said J, Reiter RE. |
| Cancer Res. 2001 Jun 15;61(12):4660-5. |
| PMID 11406532 |
| Discovery of new markers of cancer through serial analysis of gene expression: prostate stem cell antigen is overexpressed in pancreatic adenocarcinoma. |
| Argani P, Rosty C, Reiter RE, Wilentz RE, Murugesan SR, Leach SD, Ryu B, Skinner HG, Goggins M, Jaffee EM, Yeo CJ, Cameron JL, Kern SE, Hruban RH. |
| Cancer Res. 2001 Jun 1;61(11):4320-4. |
| PMID 11389052 |
| Discovery of novel tumor markers of pancreatic cancer using global gene expression technology. |
| Iacobuzio-Donahue CA, Maitra A, Shen-Ong GL, van Heek T, Ashfaq R, Meyer R, Walter K, Berg K, Hollingsworth MA, Cameron JL, Yeo CJ, Kern SE, Goggins M, Hruban RH. |
| Am J Pathol. 2002 Apr;160(4):1239-49. |
| PMID 11943709 |
| Role of prostate stem cell antigen in prostate cancer research. |
| Jalkut MW, Reiter RE. |
| Curr Opin Urol. 2002 Sep;12(5):401-6. (REVIEW) |
| PMID 12172427 |
| Prostate stem cell antigen as therapy target: tissue expression and in vivo efficacy of an immunoconjugate. |
| Ross S, Spencer SD, Holcomb I, Tan C, Hongo J, Devaux B, Rangell L, Keller GA, Schow P, Steeves RM, Lutz RJ, Frantz G, Hillan K, Peale F, Tobin P, Eberhard D, Rubin MA, Lasky LA, Koeppen H. |
| Cancer Res. 2002 May 1;62(9):2546-53. |
| PMID 11980648 |
| Prostate stem cell antigen is overexpressed in prostate cancer metastases. |
| Lam JS, Yamashiro J, Shintaku IP, Vessella RL, Jenkins RB, Horvath S, Said JW, Reiter RE. |
| Clin Cancer Res. 2005 Apr 1;11(7):2591-6. |
| PMID 15814638 |
| Prostate stem cell antigen is a putative target for immunotherapy in pancreatic cancer. |
| Wente MN, Jain A, Kono E, Berberat PO, Giese T, Reber HA, Friess H, Buchler MW, Reiter RE, Hines OJ. |
| Pancreas. 2005 Aug;31(2):119-25. |
| PMID 16024997 |
| Tissue-specificity of prostate specific antigens: comparative analysis of transcript levels in prostate and non-prostatic tissues. |
| Cunha AC, Weigle B, Kiessling A, Bachmann M, Rieber EP. |
| Cancer Lett. 2006 May 18;236(2):229-38. Epub 2005 Jul 19. |
| PMID 16046056 |
| Prostate stem cell antigen predicts tumour recurrence in superficial transitional cell carcinoma of the urinary bladder. |
| Elsamman E, Fukumori T, Kasai T, Nakatsuji H, Nishitani MA, Toida K, Ali N, Kanayama HO. |
| BJU Int. 2006 Jun;97(6):1202-7. |
| PMID 16686711 |
| The expression of prostate stem cell antigen in human clear cell renal cell carcinoma: a quantitative reverse transcriptase-polymerase chain reaction analysis. |
| Elsamman EM, Fukumori T, Tanimoto S, Nakanishi R, Takahashi M, Toida K, Kanayama HO. |
| BJU Int. 2006 Sep;98(3):668-73. |
| PMID 16925770 |
| Thy-1, a versatile modulator of signaling affecting cellular adhesion, proliferation, survival, and cytokine/growth factor responses. |
| Rege TA, Hagood JS. |
| Biochim Biophys Acta. 2006 Oct;1763(10):991-9. Epub 2006 Aug 18. |
| PMID 16996153 |
| Prostate stem cell antigen vaccination induces a long-term protective immune response against prostate cancer in the absence of autoimmunity. |
| Garcia-Hernandez Mde L, Gray A, Hubby B, Klinger OJ, Kast WM. |
| Cancer Res. 2008 Feb 1;68(3):861-9. |
| PMID 18245488 |
| Deletion of PSCA increases metastasis of TRAMP-induced prostate tumors without altering primary tumor formation. |
| Moore ML, Teitell MA, Kim Y, Watabe T, Reiter RE, Witte ON, Dubey P. |
| Prostate. 2008 Feb 1;68(2):139-51. |
| PMID 18044730 |
| Prostate stem cell antigen: A prospective therapeutic and diagnostic target. |
| Raff AB, Gray A, Kast WM. |
| Cancer Lett. 2008 Oct 4. [Epub ahead of print] (REVIEW) |
| PMID 18838214 |
| Genetic variation in PSCA is associated with susceptibility to diffuse-type gastric cancer. |
| Study Group of Millennium Genome Project for Cancer, Sakamoto H, Yoshimura K, Saeki N, Katai H, Shimoda T, Matsuno Y, Saito D, Sugimura H, Tanioka F, Kato S, Matsukura N, Matsuda N, Nakamura T, Hyodo I, Nishina T, Yasui W, Hirose H, Hayashi M, Toshiro E, Ohnami S, Sekine A, Sato Y, Totsuka H, Ando M, Takemura R, Takahashi Y, Ohdaira M, Aoki K, Honmyo I, Chiku S, Aoyagi K, Sasaki H, Ohnami S, Yanagihara K, Yoon KA, Kook MC, Lee YS, Park SR, Kim CG, Choi IJ, Yoshida T, Nakamura Y, Hirohashi S. |
| Nat Genet. 2008 Jun;40(6):730-40. Epub 2008 May 18. |
| PMID 18488030 |
| REVIEW articles | automatic search in PubMed |
| Last year publications | automatic search in PubMed |
| Contributor(s) |
| Written | 01-2009 | Adam B Raff, Andrew Gray, W Martin Kast |
| Departments of Molecular Microbiology and Immunology and Obstetrics and Gynecology, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA, USA |
| Citation |
| This paper should be referenced as such : |
| Raff AB, Gray A, Kast WM . PSCA (Prostate stem cell antigen). Atlas Genet Cytogenet Oncol Haematol. January 2009 . URL : http://AtlasGeneticsOncology.org/Genes/PSCAID41881ch8q24.html |
| © Atlas of Genetics and Cytogenetics in Oncology and Haematology | indexed on : Sat Feb 27 10:53:07 CET 2010 |
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