title: Refractory anemia with ringed sideroblasts associated with marked thrombocytosis (RARS-T), another myeloproliferative condition characterized by JAK2 V617F mutation.
abstract: JAK2 V617F mutation recently was identified as a pathogenic factor in typical chronic myeloproliferative diseases (CMPD). Some forms of myelodysplastic syndromes (MDS) show a significant overlap with CMPD (classified as MDS/MPD), but the diagnostic assignment may be challenging. We studied blood or bone marrow from 270 patients with MDS, MDS/MPD, and CMPD for the presence of JAK2 V617F mutation using polymerase chain reaction, sequencing, and melting curve analysis. The detection rate of JAK2 V617F mutants for polycythemia vera, chronic idiopathic myelofibrosis, and essential thrombocythemia (n = 103) was similar to the previously reported results. In typical forms of MDS (n = 89) JAK2 V617F mutation was very rare (n = 2). However, a higher prevalence of this mutation was found in patients with MDS/MPD-U (9 of 35). Within this group, most of the patients harboring JAK2 V617F mutation showed features consistent with the provisional MDS/MPD-U entity refractory anemia with ringed sideroblasts and thrombocytosis (RARS-T). Among 9 RARS-T patients, 6 showed the presence of JAK2 V617F mutation, and in 1 patient without mutation, aberrant, positive phospho-STAT5 staining was seen that is typically present in association with JAK2 V617F mutation. In summary, we found that RARS-T reveals a high frequency of JAK2 V617F mutation and likely constitutes another JAK2 mutation-associated form of CMPD.
authors.affiliation: Experimental Hematology and Hematopoiesis Section, R40, Taussig Cancer Center R-40, The Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH 44195, USA.
authors.forename: Hadrian
authors.initials: H
authors.lastname: Szpurka
authors.forename: Ramon
authors.initials: R
authors.lastname: Tiu
authors.forename: Gurunathan
authors.initials: G
authors.lastname: Murugesan
authors.forename: Samer
authors.initials: S
authors.lastname: Aboudola
authors.forename: Eric D
authors.initials: ED
authors.lastname: Hsi
authors.forename: Karl S
authors.initials: KS
authors.lastname: Theil
authors.forename: Mikkael A
authors.initials: MA
authors.lastname: Sekeres
authors.forename: Jaroslaw P
authors.initials: JP
authors.lastname: Maciejewski
mesh_terms: D000483:Alleles; D000756:Anemia, Sideroblastic / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D001854:Bone Marrow Cells / Q000166:cytology; D006801:Humans; D007150:Immunohistochemistry; D053614:Janus Kinase 2; D008969:Molecular Sequence Data; D009154:Mutation; D009196:Myeloproliferative Disorders / Q000235:genetics* / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D012680:Sensitivity and Specificity; D013696:Temperature; D013922:Thrombocytosis / Q000235:genetics* / Q000378:metabolism
chemical_list: D011518:Proto-Oncogene Proteins; D011505:Protein-Tyrosine Kinases; C507924:JAK2 protein, human; D053614:Janus Kinase 2