title: Phospho-ERK(THR202/Tyr214) is overexpressed in hairy cell leukemia and is a useful diagnostic marker in bone marrow trephine sections.
abstract: BRAF V600E mutations are present in virtually all cases of hairy cell leukemia (HCL). We hypothesized that detection of phospho-ERK (pERK) in tissue sections may be a useful marker for diagnosis of HCL. pERK/CD20 double immunostaining was performed on 90 formalin-fixed bone marrow trephine samples affected with small B-cell lymphoproliferative disorders, including 28 cases of HCL. pERK staining was observed in all 28 cases of HCL and in 1 of 62 cases of non-HCL B-cell lymphoproliferative disorders. By allele-specific polymerase chain reaction, all 11 cases of HCL with available DNA were positive for BRAF V600E, as was the 1 pERK non-HCL case. The remaining 31 non-HCL cases tested were negative for BRAF V600E. The sensitivity and specificity of pERK for diagnosis of HCL was 100% and 98%, respectively. We conclude that the presence of pERK as detected by immunohistochemical staining is a useful surrogate marker for BRAF V600E in the diagnosis of HCL.
authors.affiliation: Department of Clinical Pathology, Cleveland Clinic, Cleveland, OH 44195, USA.
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Warden
authors.forename: Sarah
authors.initials: S
authors.lastname: Ondrejka
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Lin
authors.forename: Lisa
authors.initials: L
authors.lastname: Durkin
authors.forename: Juraj
authors.initials: J
authors.lastname: Bodo
authors.forename: Eric D
authors.initials: ED
authors.lastname: Hsi
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism*; D001854:Bone Marrow Cells / Q000378:metabolism / Q000473:pathology; D001856:Bone Marrow Examination / Q000379:methods; D045744:Cell Line, Tumor; D004273:DNA, Neoplasm / Q000032:analysis; D003937:Diagnosis, Differential; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D006801:Humans; D007943:Leukemia, Hairy Cell / Q000175:diagnosis* / Q000201:enzymology*; D010766:Phosphorylation; D017354:Point Mutation; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D048049:Extracellular Signal-Regulated MAP Kinases