title: Immunohistochemical expression of Mum-1,  Oct-2 and Bcl-6 in systemic anaplastic large cell lymphomas.
abstract: OBJECTIVE
  Several transcription factors predominantly used for B-cell lineage identification are also expressed in a small percentage of T cells within germinal centers and interfollicular areas. The aim of the study was to evaluate the expression of Mum-1, Oct-2 and Bcl-6 in systemic anaplastic large cell lymphoma.
  
  
  METHODS
  Thirty cases of anaplastic large cell lymphoma were retrieved from our archives and tissue microarray constructed. Immunohistochemistry was carried out using an avidin-biotin peroxidase complex method.
  
  
  RESULTS
  A predominance of nuclear staining was observed for all transcription factors. Mum-1 was positive in all but one case (96.7%). Half of the cases displayed Oct-2 expression (15/30 cases). A considerable number of cases also had Bcl-6 expression (9/30). Bcl-6 staining was noted to be more common in ALK positive cases.
  
  
  CONCLUSIONS
  Our findings emphasize that these markers are not restricted to B-cell lineage and that extensive expression can be observed in anaplastic large cell lymphoma of T/null cell phenotype.
authors.affiliation: Hacettepe University Faculty of Medicine, Department of Pathology, Sihhiye, Ankara, Turkey.
authors.forename: Arzu
authors.initials: A
authors.lastname: Saglam
authors.forename: Aysegul H
authors.initials: AH
authors.lastname: Uner
mesh_terms: D000077548:Anaplastic Lymphoma Kinase; D014408:Biomarkers, Tumor / Q000032:analysis*; D004268:DNA-Binding Proteins / Q000032:analysis*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D050835:Interferon Regulatory Factors / Q000032:analysis*; D017728:Lymphoma, Large-Cell, Anaplastic / Q000737:chemistry* / Q000473:pathology; D050813:Octamer Transcription Factor-2 / Q000032:analysis*; D051560:Proto-Oncogene Proteins c-bcl-6; D020794:Receptor Protein-Tyrosine Kinases / Q000032:analysis*; D046888:Tissue Array Analysis; D000099218:Interferon Regulatory Factor-4
chemical_list: D000077548:Anaplastic Lymphoma Kinase; D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; D050835:Interferon Regulatory Factors; D050813:Octamer Transcription Factor-2; D051560:Proto-Oncogene Proteins c-bcl-6; D020794:Receptor Protein-Tyrosine Kinases; D000099218:Interferon Regulatory Factor-4; C084103:BCL6 protein, human; C058435:POU2F2 protein, human; C000626173:ALK protein, human