title: Immediate early response gene X-1, a potential prognostic biomarker in cancers.
abstract: BACKGROUND
  The immediate early response gene X-1 (IEX-1) plays a pivotal role in the regulation of cell apoptosis, proliferation, differentiation and metabolism. Deregulation of IEX-1 expression has been confirmed in multiple cancers in humans, in association with either poor or better prognosis depending on the type and progression stages of the cancer.
  
  
  METHODS
  This review summarizes clinical studies of altered IEX-1 expression in ovarian, pancreatic, blood, breast and colorectal cancers, lymphoma and myeloma. The authors also outline the current understandings of the complex functions of IEX-1 gained from studies with animal models and tumor cell lines so as to help us comprehend the significance of the clinical findings.
  
  
  CONCLUSIONS
  IEX-1 holds great promise to be a valuable biomarker, either alone or in combination with other genes, for monitoring progression of some cancers. IEX-1 expression is highly sensitive to environmental cues and distinct between normal and cancer cells. However, use of IEX-1 as a biomarker remains a significant challenge because too little is understood about the mechanism underlying the diverse activities of IEX-1 and a standardized clinical assay for IEX-1 detection and validation of clinical results across different studies are still critically lacking.
authors: Massachusetts General Hospital and Harvard Medical School, Wellman Center for Photomedicine, Department of Dermatology , Edwards 222, 50 Blossom Street, Boston, MA 02114, USA. mwu2@partners.org
authors: Mei X
authors: MX
authors: Wu
authors: Irina V
authors: IV
authors: Ustyugova
authors: Liping
authors: L
authors: Han
authors: Oleg E
authors: OE
authors: Akilov
mesh_terms: D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000235:genetics*; D014408:Biomarkers, Tumor / Q000235:genetics*; D017781:Genes, Immediate-Early; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics*; D009369:Neoplasms / Q000175:diagnosis / Q000235:genetics*; D011379:Prognosis
chemical_list: D051017:Apoptosis Regulatory Proteins; D014408:Biomarkers, Tumor; C099815:IER3 protein, human; D008565:Membrane Proteins
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