title: Aberrant nuclear repressor coreceptor 1 localization in human retinoblastoma.
abstract: OBJECTIVE
  Nuclear receptor corepressor 1 (NCoR1) is a protein complex with diverse functions in development and tumorigenesis. We investigated the pattern of expression and histopathological correlation of NCoR1 in 41 retinoblastoma tumor samples, 1 retinoblastoma cell line (WERI-Rb-1) and human retinal progenitor cells (hRPCs).
  
  
  METHODS
  Tissue sections from 41 retinoblastoma cases, the retinoblastoma cell line WERI-Rb-1 and hRPCs were stained with rabbit polyclonal anti-NCoR1 H76 antibody. Percentage and intensity of staining were classified by an ocular pathologist from 0 to 3. The paired t test was used to test for differences.
  
  
  RESULTS
  In the nonneoplastic retina, NCoR1 was expressed mainly in cell nuclei. The retinoblastoma tumor cells similarly had nuclear NCoR1 but also had a higher level of cytoplasmic NCoR1 expression compared to all 3 normal retinal cell layers (p < 0.002). In contrast to the normal retina, NCoR1 was mainly expressed in the cytoplasm of the proliferating WERI-Rb-1 cells. This cytoplasmic expression pattern was also seen in the undifferentiated hRPCs.
  
  
  CONCLUSIONS
  The aberrant cytoplasmic expression of NCoR1 in retinoblastoma appears to be associated with the proliferative and/or dedifferentiated properties of retinoblastoma. Further investigation into the role of NCoR1 in retinoblastoma may provide insight into how therapeutically inhibiting its nucleocytoplasmic shuttling may affect retinoblastoma tumor biology.
authors.affiliation: Henry C. Witelson Ocular Pathology Laboratory, Department of Ophthalmology, McGill University, Montreal, Que., Canada. bkn02@aub.edu.lb
authors.forename: Bassel
authors.initials: B
authors.lastname: Nazha
authors.forename: Tamara
authors.initials: T
authors.lastname: Granner
authors.forename: Shawn
authors.initials: S
authors.lastname: Maloney
authors.forename: Alexandre N
authors.initials: AN
authors.lastname: Odashiro
authors.forename: Emilia
authors.initials: E
authors.lastname: Antecka
authors.forename: Miguel N
authors.initials: MN
authors.lastname: Burnier
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D009363:Neoplasm Proteins / Q000378:metabolism*; D056971:Nuclear Receptor Co-Repressor 1 / Q000378:metabolism*; D019572:Retinal Neoplasms / Q000378:metabolism* / Q000473:pathology; D012175:Retinoblastoma / Q000378:metabolism* / Q000473:pathology; D013347:Subcellular Fractions; D014407:Tumor Cells, Cultured
chemical_list: D014408:Biomarkers, Tumor; C539127:NCOR1 protein, human; D009363:Neoplasm Proteins; D056971:Nuclear Receptor Co-Repressor 1