title: Detection of immunoglobulin light-chain restriction in cutaneous B-cell lymphomas by ultrasensitive bright-field mRNA in situ hybridization.
abstract: BACKGROUND
  Detection of immunoglobulin light-chain restriction is important in the diagnosis of B-cell non-Hodgkin lymphoma (B-NHL). Flow-cytometry, commonly used to evaluate light-chain restriction, is impractical to be used in cutaneous specimens. Immunohistochemical and conventional chromogenic in situ hybridization (CISH) methods on formalin-fixed-paraffin-embedded (FFPE) tissue lack sufficient sensitivity to detect low-level light-chain expression in B-NHL without plasmacytic differentiation. Ultrasensitive bright-field mRNA-ISH (BRISH) for in situ light-chain detection in cutaneous B-NHL has been assessed.
  
  
  METHODS
  Kappa/lambda mRNA was detected using two-color BRISH (RNAscope 2xPlex, Advanced Cell Diagnostics) on 27 FFPE skin biopsies and excisions from patients with available B-cell PCR clonality studies: 16 clonal B-cell lesions (6 follicle center lymphoma, 5 marginal zone lymphoma, 3 large B-cell lymphoma, and 2 other) and 11 non-clonal B-cell proliferations.
  
  
  RESULTS
  BRISH was successful in 15/16 clonal B-cell lesions and 11/11 non-clonal proliferations. Light-chain restriction was detected in 15/15 clonal lesions and in 1/11 non-clonal proliferations (96.1% overall concordance with clonality PCR). In 4/5 marginal zone lymphomas, light-chain restriction was detected as strong monotypic mRNA expression in a B-cell subset, consistent with plasmacytic differentiation.
  
  
  CONCLUSIONS
  Ultrasensitive BRISH can successfully detect light-chain restriction in B-NHL from FFPE skin specimens and may be a useful adjunct ancillary tool in cases not resolved by CISH or immunohistochemical methods.
authors.affiliation: Department of Pathology, Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Eugen C
authors.initials: EC
authors.lastname: Minca
authors.forename: Hongwei
authors.initials: H
authors.lastname: Wang
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.forename: Christopher
authors.initials: C
authors.lastname: Lanigan
authors.forename: Steven D
authors.initials: SD
authors.lastname: Billings
authors.forename: Yuling
authors.initials: Y
authors.lastname: Luo
authors.forename: Raymond R
authors.initials: RR
authors.lastname: Tubbs
authors.forename: Xiao-Jun
authors.initials: XJ
authors.lastname: Ma
mesh_terms: D001402:B-Lymphocytes / Q000473:pathology; D005434:Flow Cytometry; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000235:genetics*; D007145:Immunoglobulin kappa-Chains / Q000235:genetics*; D007146:Immunoglobulin lambda-Chains / Q000235:genetics*; D007150:Immunohistochemistry / Q000379:methods; D017403:In Situ Hybridization / Q000379:methods*; D016393:Lymphoma, B-Cell / Q000175:diagnosis* / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000032:analysis* / Q000378:metabolism; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology
chemical_list: D007147:Immunoglobulin Light Chains; D007145:Immunoglobulin kappa-Chains; D007146:Immunoglobulin lambda-Chains; D012333:RNA, Messenger
keywords: cutaneous; in situ hybridization; kappa/lambda; lymphoma; skin