title: CALR, JAK2, and MPL mutation profiles in patients with four different subtypes of myeloproliferative neoplasms: primary myelofibrosis, essential thrombocythemia, polycythemia vera, and myeloproliferative neoplasm, unclassifiable.
abstract: OBJECTIVE
  We investigated mutation profiles of CALR, JAK2, and MPL in 199 Korean patients with myeloproliferative neoplasms (MPNs).
  
  
  METHODS
  In total, 199 patients with MPN (54 primary myelofibrosis [PMF], 79 essential thrombocythemia [ET], 58 polycythemia vera [PV], and eight MPN-unclassifiable [MPN-U]) and 4 patients with acute panmyelosis with myelofibrosis (APMF) were retrospectively subjected to Sanger sequencing for CALR, JAK2, and MPL.
  
  
  RESULTS
  The overall frequency of CALR mutations was 12.6% (type 1 mutation, 16 patients; type 2 mutation, nine patients): most frequent in MPN-U (37.5%), followed by ET (17.7%) and PMF (14.8%). CALR mutations were not found in PV or APMF. CALR and JAK2 or MPL mutations were mutually exclusive. In PMF, the CALR mutations were associated with lower levels of leukocytes, lower bone marrow cellularity, and higher number of megakaryocytes. Patients with CALR-mutated ET more frequently progressed to the accelerated or blast phases compared with patients with JAK2 mutations. CALR mutations were frequently observed in the JAK2-negative MPNs, most frequently in MPN-U.
  
  
  CONCLUSIONS
  The prognostic significance of CALR mutations likely differs among the MPN subtypes.
authors: From the Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea; and.
authors: Seon Young
authors: SY
authors: Kim
authors: Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors: Kyongok
authors: K
authors: Im
authors: Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors: Si Nae
authors: SN
authors: Park
authors: Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors: Jiseok
authors: J
authors: Kwon
authors: From the Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea; and.
authors: Jung-Ah
authors: JA
authors: Kim
authors: From the Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea; and Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea. soonlee@snu.ac.kr.
authors: Dong Soon
authors: DS
authors: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D037282:Calreticulin / Q000235:genetics*; D002648:Child; D004502:Education, Medical, Continuing; D005260:Female; D006801:Humans; D053614:Janus Kinase 2 / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009196:Myeloproliferative Disorders / Q000235:genetics*; D011087:Polycythemia Vera / Q000235:genetics*; D055728:Primary Myelofibrosis / Q000235:genetics*; D011379:Prognosis; D053628:Receptors, Thrombopoietin / Q000235:genetics*; D056910:Republic of Korea; D016019:Survival Analysis; D013920:Thrombocythemia, Essential / Q000235:genetics*; D055815:Young Adult
chemical_list: C576483:CALR protein, human; D037282:Calreticulin; D053628:Receptors, Thrombopoietin; C082218:MPL protein, human; C507924:JAK2 protein, human; D053614:Janus Kinase 2
keywords: Calreticulin; JAK2; Myeloproliferative neoplasms; Somatic mutation