title: Evaluation of allele-specific PCR and immunohistochemistry for the detection of BRAF V600E mutations in hairy cell leukemia.
abstract: OBJECTIVE
  Detection of BRAF V600E mutations in hairy cell leukemia (HCL) has important diagnostic utility. In this study, we sought to compare immunohistochemistry with an antibody specific for this mutation to a sensitive molecular assay.
  
  
  METHODS
  The performance of the BRAF V600E-specific VE1 antibody was compared with that of allele-specific polymerase chain reaction (PCR) in 22 formalin-fixed, paraffin-embedded (FFPE) specimens with HCL involvement, along with nine splenic marginal zone lymphomas (SMZLs), 10 follicular lymphomas (FLs), 10 mantle cell lymphomas (MCLs), and 10 chronic lymphocytic leukemia/small lymphocytic lymphomas (CLL/SLLs). An additional 11 SMZLs, 100 FLs, 20 MCLs, 83 CLL/SLL specimens, and 49 reactive tonsils within tissue microarrays were stained with VE1.
  
  
  RESULTS
  A BRAF V600E mutation was detected in 17 (77.3%) of 22 HCL cases by PCR. Immunohistochemistry demonstrated VE1 staining in 20 (90.9%) cases, identifying low-level (~1%) involvement in three HCL cases that were mutation negative by PCR. Evaluation of additional material from these patients confirmed the presence of BRAF V600E. Thirty-nine non-HCL cases were negative by both methods. Within tissue microarrays, weak false-positive staining was observed in two (0.8%) of 263 non-HCL cases.
  
  
  CONCLUSIONS
  VE1 immunohistochemistry is more sensitive than allele-specific PCR in FFPE bone marrow specimens and can be applied to decalcified core biopsy specimens that are not appropriate for molecular techniques.
authors.affiliation: From the Department of Pathology, University of Michigan, Ann Arbor.
authors.forename: Noah A
authors.initials: NA
authors.lastname: Brown
authors.affiliation: From the Department of Pathology, University of Michigan, Ann Arbor.
authors.forename: Bryan L
authors.initials: BL
authors.lastname: Betz
authors.affiliation: From the Department of Pathology, University of Michigan, Ann Arbor.
authors.forename: Helmut C
authors.initials: HC
authors.lastname: Weigelin
authors.affiliation: From the Department of Pathology, University of Michigan, Ann Arbor.
authors.forename: Kojo S J
authors.initials: KS
authors.lastname: Elenitoba-Johnson
authors.affiliation: From the Department of Pathology, University of Michigan, Ann Arbor.
authors.forename: Megan S
authors.initials: MS
authors.lastname: Lim
authors.affiliation: From the Department of Pathology, University of Michigan, Ann Arbor. ngbailey@umich.edu.
authors.forename: Nathanael G
authors.initials: NG
authors.lastname: Bailey
mesh_terms: D000328:Adult; D000483:Alleles; D014408:Biomarkers, Tumor / Q000235:genetics; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007943:Leukemia, Hairy Cell / Q000175:diagnosis* / Q000235:genetics; D016393:Lymphoma, B-Cell / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D016133:Polymerase Chain Reaction; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*
chemical_list: D014408:Biomarkers, Tumor; D048493:Proto-Oncogene Proteins B-raf
keywords: Allele-specific PCR; Antibody; BRAF; Hairy cell leukemia; Immunohistochemistry; PCR; VE1