title: Evaluation of a new paraffin-reactive CD7 T-cell deletion marker and a polymerase chain reaction-based T-cell receptor gene rearrangement assay: implications for diagnosis of mycosis fungoides in community clinical practice.
abstract: BACKGROUND
  T-cell deletion and T-cell receptor (TCR) gene rearrangement studies are helpful in the early diagnosis and subsequent management of mycosis fungoides (MF). However, this often requires fresh-frozen tissue that can be difficult to obtain and evaluate in community clinical practice. A new CD7 antibody, the most sensitive and specific T-cell deletion marker, and a new TCR-gamma gene rearrangement polymerase chain reaction (PCR) assay (TCR-gamma PCR) are now available on routine paraffin-embedded biopsy specimens.
  
  
  OBJECTIVE
  Our purpose was to assess the utility of CD7 deletion and TCR-gamma PCR in the diagnosis of MF using routine paraffin-embedded biopsy material.
  
  
  METHODS
  Cases of MF (n = 17) with matching frozen tissue immunohistochemistry and benign reactive dermatoses (lichen planus; n = 27) were assessed for CD7 (Clone: CD7-272) deletion and TCR-gamma PCR using paraffin-embedded biopsy specimens.
  
  
  RESULTS
  Excellent concordance comparing frozen and paraffin embedded CD7 immunostaining (88%) was observed. CD7 deletion and TCR-gamma PCR was sensitive (94%) and specific (96%) for a diagnosis of MF using paraffin-embedded biopsy specimens.
  
  
  CONCLUSIONS
  In the diagnosis of MF, detection of CD7 deletion and monoclonal TCR rearrangements can be successfully performed in a cost-effective, timely fashion using routine formalin-fixed paraffin-embedded biopsy specimens.
authors.affiliation: Department of Anatomic Pathology and Dermatology, The Cleveland Clinic Foundation, 9500 Euclid Ave., Cleveland, OH 44195, USA.
authors.forename: A
authors.initials: A
authors.lastname: Ormsby
authors.forename: W F
authors.initials: WF
authors.lastname: Bergfeld
authors.forename: R R
authors.initials: RR
authors.lastname: Tubbs
authors.forename: E D
authors.initials: ED
authors.lastname: Hsi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal; D019011:Antigens, CD7; D017931:DNA Primers; D005260:Female; D017353:Gene Deletion; D015334:Gene Rearrangement, gamma-Chain T-Cell Antigen Receptor / Q000235:genetics*; D019675:Genes, T-Cell Receptor gamma / Q000235:genetics; D006801:Humans; D008010:Lichen Planus / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009182:Mycosis Fungoides / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D016612:Paraffin Embedding; D016133:Polymerase Chain Reaction / Q000592:standards; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology
chemical_list: D000911:Antibodies, Monoclonal; D019011:Antigens, CD7; D017931:DNA Primers