title: Detection of TET2 abnormalities by fluorescence in situ hybridization in 41 patients with myelodysplastic syndrome.
abstract: TET2 haplo-insufficiency occurs through different molecular mechanisms and is promptly revealed by array comparative genomic hybridization, single nucleotide polymorphism (SNP) array, and next-generation sequencing (NGS). Fluorescence in situ hybridization (FISH) can effectively demonstrate TET2 deletions and is often used to validate molecular results. In the present study 41 MDS patients with and without 4q abnormalities were analyzed with a series of bacterial artificial chromosome (BAC) probes spanning the 4q22.3-q25 region. On conventional cytogenetic (CC) studies, a structural defect of the long arm of chromosome 4 (4q) was observed in seven patients. In three, one each with a t(1;4)(p21;q24), an ins(5;4)(q23;q24qter), and a t(4;17)(q31;p13) as the sole chromosomal abnormality, FISH with the RP11-356L5 and RP11-16G16 probes, which cover the TET2 locus, produced one signal only. Unexpectedly, this same result was achieved in 3 of the remaining 34 patients. Thus, a TET2 deletion was observed in a total of six patients (14.6%). TET2 deletion was not correlated with any particular clinical findings or outcome. These findings demonstrate that 1) FISH is an effective and economical method to reveal cryptic abnormalities of band 4q22-q24 resulting in TET2 deletions; 2) in these patients, TET2 deletion is the unifying genetic event; and 3) the different breakpoints within the 4q22-q25 region suggest that deletions are not mediated by repetitive sequences.
authors: Division of Hematology, Fondazione IRCCS Policlinico San Matteo, University of Pavia, Italy. i.dambruoso@smatteo.pv.it
authors: Irene
authors: I
authors: Dambruoso
authors: Marina
authors: M
authors: Boni
authors: Marianna
authors: M
authors: Rossi
authors: Patrizia
authors: P
authors: Zappasodi
authors: Celeste
authors: C
authors: Calvello
authors: Rita
authors: R
authors: Zappatore
authors: Paola Maria
authors: PM
authors: Cavigliano
authors: Ilaria
authors: I
authors: Giardini
authors: Barbara
authors: B
authors: Rocca
authors: Marilena
authors: M
authors: Caresana
authors: Cesare
authors: C
authors: Astori
authors: Mario
authors: M
authors: Cazzola
authors: Carlo
authors: C
authors: Castagnola
authors: Paolo
authors: P
authors: Bernasconi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000782:Aneuploidy; D002871:Chromosome Banding; D002894:Chromosomes, Human, Pair 4 / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D049308:Dioxygenases; D005260:Female; D057895:Haploinsufficiency; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D007621:Karyotyping; D008297:Male; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D017384:Sequence Deletion; D014178:Translocation, Genetic
chemical_list: D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D049308:Dioxygenases; C541081:TET2 protein, human