title: The prevalence of CALR mutations in a cohort of patients with myeloproliferative neoplasms.
abstract: BACKGROUND
  To investigate the prevalence of calreticulin (CALR) mutations in JAK2- and MPL-non-mutated patients with suspected myeloproliferative neoplasm (MPN) from a large MPN clinic and confirm a diagnosis of MPN.
  
  
  METHODS
  JAK2/MPL-non-mutated patients from the Belfast City Hospital (BCH) with either of the MPNs - ET or MF - and diagnosed between 1988 and 2014 were selected for CALR screen. All cases were validated according to the WHO 2008 classification for MPNs. Statistical analysis was performed with Minitab 16 Statistical Software package. Exon 9 of CALR was amplified by PCR using genomic DNA, and mutations were detected by fragment analysis.
  
  
  RESULTS
  Of the 62 JAK2/MPL-non-mutated MPN patients screened, 57 had ET and 5 had MF; 34 patients (53.1%) carried CALR mutations. Three of 5 MF patients were CALR positive. Thirty-one ET patients (54.3%) harboured CALR mutation, whereas 26 (45.7%) were classified as 'triple negatives'.
  
  
  CONCLUSIONS
  Detection of CALR mutations in a cohort of JAK2/MPL-non-mutated patients with suspected MPN confirmed the diagnosis of MPN in around 53% of cases. This is lower than initially reported, but similar to subsequent studies. However, a sizable cohort of patients remains lacking a specific molecular marker.
authors.affiliation: Medicine, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.|Queens University of Belfast, Belfast, UK.|Instituto Nacional de Infectologia Evandro Chagas - Fiocruz, Rio de Janeiro, Brazil.
authors.forename: E
authors.initials: E
authors.lastname: Grinsztejn
authors.affiliation: Haematology, Belfast City Hospital, Belfast, UK.
authors.forename: M J
authors.initials: MJ
authors.lastname: Percy
authors.affiliation: Haematology, Belfast City Hospital, Belfast, UK.
authors.forename: D
authors.initials: D
authors.lastname: McClenaghan
authors.affiliation: Instituto Nacional de Infectologia Evandro Chagas - Fiocruz, Rio de Janeiro, Brazil.
authors.forename: M
authors.initials: M
authors.lastname: Quintana
authors.affiliation: Haematology, Belfast City Hospital, Belfast, UK.
authors.forename: R J G
authors.initials: RJ
authors.lastname: Cuthbert
authors.affiliation: Queens University of Belfast, Belfast, UK.|Haematology, Belfast City Hospital, Belfast, UK.
authors.forename: M F
authors.initials: MF
authors.lastname: McMullin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D037282:Calreticulin / Q000235:genetics*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D053614:Janus Kinase 2 / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009196:Myeloproliferative Disorders / Q000175:diagnosis* / Q000235:genetics* / Q000401:mortality; D015995:Prevalence; D011379:Prognosis; D053628:Receptors, Thrombopoietin / Q000235:genetics
chemical_list: C576483:CALR protein, human; D037282:Calreticulin; D053628:Receptors, Thrombopoietin; C507924:JAK2 protein, human; D053614:Janus Kinase 2
keywords: Myeloproliferative; calreticulin; mutations; prevalence; prognosis