Mutation in TET2 in myeloid cancers.
BACKGROUND
The myelodysplastic syndromes and myeloproliferative disorders are associated with deregulated production of myeloid cells. The mechanisms underlying these disorders are not well defined.


METHODS
We conducted a combination of molecular, cytogenetic, comparative-genomic-hybridization, and single-nucleotide-polymorphism analyses to identify a candidate tumor-suppressor gene common to patients with myelodysplastic syndromes, myeloproliferative disorders, and acute myeloid leukemia (AML). The coding sequence of this gene, TET2, was determined in 320 patients. We analyzed the consequences of deletions or mutations in TET2 with the use of in vitro clonal assays and transplantation of human tumor cells into mice.


RESULTS
We initially identified deletions or mutations in TET2 in three patients with myelodysplastic syndromes, in three of five patients with myeloproliferative disorders, in two patients with primary AML, and in one patient with secondary AML. We selected the six patients with myelodysplastic syndromes or AML because they carried acquired rearrangements on chromosome 4q24; we selected the five patients with myeloproliferative disorders because they carried a dominant clone in hematopoietic progenitor cells that was positive for the V617F mutation in the Janus kinase 2 (JAK2) gene. TET2 defects were observed in 15 of 81 patients with myelodysplastic syndromes (19%), in 24 of 198 patients with myeloproliferative disorders (12%) (with or without the JAK2 V617F mutation), in 5 of 21 patients with secondary AML (24%), and in 2 of 9 patients with chronic myelomonocytic leukemia (22%). TET2 defects were present in hematopoietic stem cells and preceded the JAK2 V617F mutation in the five samples from patients with myeloproliferative disorders that we analyzed.


CONCLUSIONS
Somatic mutations in TET2 occur in about 15% of patients with various myeloid cancers.
Delhommeau
François
F
INSERM U790, Institut Gustave Roussy, Villejuif, France.
Dupont
Sabrina
S
Della Valle
Véronique
V
James
Chloé
C
Trannoy
Severine
S
Massé
Aline
A
Kosmider
Olivier
O
Le Couedic
Jean-Pierre
JP
Robert
Fabienne
F
Alberdi
Antonio
A
Lécluse
Yann
Y
Plo
Isabelle
I
Dreyfus
François J
FJ
Marzac
Christophe
C
Casadevall
Nicole
N
Lacombe
Catherine
C
Romana
Serge P
SP
Dessen
Philippe
P
Soulier
Jean
J
Viguié
Franck
F
Fontenay
Michaela
M
Vainchenker
William
W
Bernard
Olivier A
OA
D000595:Amino Acid Sequence; D000818:Animals; D018952:Antigens, CD34; D002894:Chromosomes, Human, Pair 4 / Q000235:genetics; D055028:Comparative Genomic Hybridization; D004268:DNA-Binding Proteins / Q000235:genetics*; D049308:Dioxygenases; D015321:Gene Rearrangement; D006412:Hematopoietic Stem Cells / Q000276:immunology; D006801:Humans; D053614:Janus Kinase 2 / Q000235:genetics; D015470:Leukemia, Myeloid, Acute / Q000235:genetics*; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D008969:Molecular Sequence Data; D009154:Mutation; D009190:Myelodysplastic Syndromes / Q000235:genetics*; D009196:Myeloproliferative Disorders / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D017384:Sequence Deletion
D018952:Antigens, CD34; D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D049308:Dioxygenases; C541081:TET2 protein, human; C507924:JAK2 protein, human; D053614:Janus Kinase 2