title: Next-generation sequencing of the TET2 gene in 355 MDS and CMML patients reveals low-abundance mutant clones with early origins, but indicates no definite prognostic value.
abstract: Mutations in the TET2 gene are frequent in myeloid disease, although their biologic and prognostic significance remains unclear. We analyzed 355 patients with myelodysplastic syndromes using "next-generation" sequencing for TET2 aberrations, 91 of whom were also subjected to single-nucleotide polymorphism 6.0 array karyotyping. Seventy-one TET2 mutations, with a relative mutation abundance (RMA) ≥ 10%, were identified in 39 of 320 (12%) myelodysplastic syndrome and 16 of 35 (46%) chronic myelomonocytic leukemia patients (P < .001). Interestingly, 4 patients had multiple mutations likely to exist as independent clones or on alternate alleles, suggestive of clonal evolution. "Deeper" sequencing of 96 patient samples identified 4 additional mutations (RMA, 3%-6.3%). Importantly, TET2 mutant clones were also found in T cells, in addition to CD34(+) and total bone marrow cells (23.5%, 38.5%, and 43% RMA, respectively). Only 20% of the TET2-mutated patients showed loss of heterozygosity at the TET2 locus. There was no difference in the frequency of genome-wide aberrations, TET2 expression, or the JAK2V617F 46/1 haplotype between TET2-mutated and nonmutated patients. There was no significant prognostic association between TET2 mutations and World Health Organization subtypes, International Prognostic Scoring System score, cytogenetic status, or transformation to acute myeloid leukemia. On multivariate analysis, age (> 50 years) was associated with a higher incidence of TET2 mutation (P = .02).
authors.affiliation: Department of Hematologic Medicine, King's College London School of Medicine, London, United Kingdom.
authors.forename: Alexander E
authors.initials: AE
authors.lastname: Smith
authors.forename: Azim M
authors.initials: AM
authors.lastname: Mohamedali
authors.forename: Austin
authors.initials: A
authors.lastname: Kulasekararaj
authors.forename: ZiYi
authors.initials: Z
authors.lastname: Lim
authors.forename: Joop
authors.initials: J
authors.lastname: Gäken
authors.forename: Nicholas C
authors.initials: NC
authors.lastname: Lea
authors.forename: Bartlomiej
authors.initials: B
authors.lastname: Przychodzen
authors.forename: Syed A
authors.initials: SA
authors.lastname: Mian
authors.forename: Erick E
authors.initials: EE
authors.lastname: Nasser
authors.forename: Claire
authors.initials: C
authors.lastname: Shooter
authors.forename: Nigel B
authors.initials: NB
authors.lastname: Westwood
authors.forename: Corinna
authors.initials: C
authors.lastname: Strupp
authors.forename: Norbert
authors.initials: N
authors.lastname: Gattermann
authors.forename: Jaroslaw P
authors.initials: JP
authors.lastname: Maciejewski
authors.forename: Ulrich
authors.initials: U
authors.lastname: Germing
authors.forename: Ghulam J
authors.initials: GJ
authors.lastname: Mufti
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019943:Amino Acid Substitution; D001483:Base Sequence; D002454:Cell Differentiation / Q000235:genetics; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000235:genetics*; D049308:Dioxygenases; D005260:Female; D015870:Gene Expression; D006801:Humans; D053614:Janus Kinase 2 / Q000235:genetics; D007621:Karyotyping; D015477:Leukemia, Myelomonocytic, Chronic / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D019656:Loss of Heterozygosity; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009154:Mutation; D009190:Myelodysplastic Syndromes / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D020641:Polymorphism, Single Nucleotide; D011379:Prognosis; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D016019:Survival Analysis; D013601:T-Lymphocytes / Q000378:metabolism; D055815:Young Adult
chemical_list: D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D049308:Dioxygenases; C541081:TET2 protein, human; C507924:JAK2 protein, human; D053614:Janus Kinase 2