title: A new monoclonal antibody (CAL2) detects CALRETICULIN mutations in formalin-fixed and paraffin-embedded bone marrow biopsies.
abstract: Recent advances in the diagnostic of myeloproliferative neoplasms (MPNs) discovered CALRETICULIN (CALR) mutations as a major driver in these disorders. In contrast to JAK2 mutations being mainly associated with polycythaemia vera, CALR mutations are only associated with primary myelofibrosis (PMF) and essential thrombocythaemia (ET). CALR mutations are present in the majority of PMF and ET patients lacking JAK2 and MPL mutations. As these CALR mutations are absent from reactive bone marrow (BM) lesions their presence indicates ET or PMF. So far these mutations are detectable only by molecular assays. Their molecular detection is cumbersome because of the great CALR mutation heterogeneity. Therefore, the availability of a simple assay would be of great help. All CALR mutations reported lead to a frameshift generating a new 36 amino-acid C-terminus. We generated a monoclonal antibody (CAL2) to this C-neoterminus by immunizing mice with a representative peptide and compared its performance with Sanger sequencing data in 173 MPNs and other BM diseases. There was a 100% correlation between the molecular and the CAL2 immunohistochemical (IHC) assays. Thus, the detection of CALR mutations by the CAL2 IHC is a specific, sensitive, rapid, simple and low-cost method.
authors.affiliation: Reference and Consultation Center for Lymphoma and Haematopathology, Pathodiagnostik Berlin, Berlin, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Stein
authors.affiliation: Reference and Consultation Center for Lymphoma and Haematopathology, Pathodiagnostik Berlin, Berlin, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Bob
authors.affiliation: Reference and Consultation Center for Lymphoma and Haematopathology, Pathodiagnostik Berlin, Berlin, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Dürkop
authors.affiliation: Synaptic Systems GmbH, Göttingen, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Erck
authors.affiliation: Praxis für Onkologie, Lüdenscheid, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Kämpfe
authors.affiliation: Senckenbergisches Institut für Pathologie, Johann Wolfgang Goethe-Universität, Frankfurt am Main, Germany.
authors.forename: H-M
authors.initials: HM
authors.lastname: Kvasnicka
authors.affiliation: Synaptic Systems GmbH, Göttingen, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Martens
authors.affiliation: Medizinisches Versorgungszentrum am Helios Klinikum Emil von Behring, Labor für molekulare Diagnostik und Mikrobiologie, Berlin, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Roth
authors.affiliation: Medizinisches Versorgungszentrum am Helios Klinikum Emil von Behring, Labor für molekulare Diagnostik und Mikrobiologie, Berlin, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Streubel
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D001706:Biopsy; D001853:Bone Marrow / Q000737:chemistry*; D037282:Calreticulin / Q000032:analysis / Q000235:genetics*; D005557:Formaldehyde; D057809:HEK293 Cells; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D016612:Paraffin Embedding
chemical_list: D000911:Antibodies, Monoclonal; C576483:CALR protein, human; D037282:Calreticulin; D005557:Formaldehyde