title: Differential expression of TOX by skin-infiltrating T cells in Sézary syndrome and erythrodermic dermatitis.
abstract: BACKGROUND
  The histopathologic differentiation between Sézary syndrome (SS) and erythrodermic dermatitis may be extremely difficult. In this immunohistochemical study, it was investigated if thymocyte selection-associated high mobility group box protein (TOX) and C-MYC can be used as additional diagnostic markers to differentiate between SS and erythrodermic dermatitis.
  
  
  METHODS
  Paraffin-embedded skin biopsies from 15 SS patients and 17 erythrodermic dermatitis patients were stained and scored for TOX or C-MYC expression.
  
  
  RESULTS
  Strong nuclear staining for TOX in more than 50% of skin-infiltrating T cells was observed in 13 of 15 (87%) SS cases, whereas erythrodermic dermatitis cases showed weak nuclear staining in 11-50% (median: 25%) of the T cells; strong nuclear staining as found in SS was never observed in erythrodermic dermatitis. No significant differences in C-MYC expression between SS and erythrodermic dermatitis were found. In most patients of both groups, percentages of C-MYC positive-cells varied between less than 10 and 25% of skin-infiltrating T cells.
  
  
  CONCLUSIONS
  Our results suggest that strong expression of TOX in more than 50% of skin-infiltrating T cells in erythrodermic skin is a useful marker in the differentiation between SS and erythrodermic dermatitis, whereas staining for C-MYC does not contribute to differential diagnosis.
authors.affiliation: Department of Dermatology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Stephanie E
authors.initials: SE
authors.lastname: Boonk
authors.affiliation: Department of Dermatology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Fatma
authors.initials: F
authors.lastname: Çetinözman
authors.affiliation: Department of Dermatology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Maarten H
authors.initials: MH
authors.lastname: Vermeer
authors.affiliation: Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Patty M
authors.initials: PM
authors.lastname: Jansen
authors.affiliation: Department of Dermatology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Rein
authors.initials: R
authors.lastname: Willemze
mesh_terms: D001706:Biopsy; D004268:DNA-Binding Proteins / Q000378:metabolism; D003873:Dermatitis, Exfoliative / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology; D003937:Diagnosis, Differential; D006609:High Mobility Group Proteins / Q000096:biosynthesis*; D006801:Humans; D007150:Immunohistochemistry; D012751:Sezary Syndrome / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology*; D012867:Skin / Q000473:pathology; D013601:T-Lymphocytes / Q000378:metabolism* / Q000473:pathology*; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D006609:High Mobility Group Proteins; C116115:MYCBP protein, human; C558851:TOX protein, human; D014157:Transcription Factors
keywords: C-MYC; Sézary syndrome; TOX; erythroderma; immunohistochemistry