title: Development of a dual-color, double fusion FISH assay to detect RPN1/EVI1 gene fusion associated with inv(3), t(3;3), and ins(3;3) in patients with myelodysplasia and acute myeloid leukemia.
abstract: Approximately 2-3% of adult patients with acute myeloid leukemia harbor a rearrangement of RPN1 (at 3q21) and EVI1 (at 3q26.2) as inv(3)(q21q26.2), t(3;3)(q21;q26.2), or ins(3;3)(q26.2;q21q26.2). The most recent World Health Organization (WHO) classification has designated AML with inv(3) or t(3;3) and associated RPN1/EVI1 fusion, as a distinct AML subgroup associated with an unfavorable prognosis. We have created a dual color, double fusion fluorescence in situ hybridization (D-FISH) assay to detect fusion of the RPN1 and EVI1 genes. A blinded investigation was performed using 30 normal bone marrow samples and 51 bone marrow samples from 17 patients with inv(3)(q21q26.2), 11 patients with t(3;3)(q21;q26.2), and one patient with ins(3;3)(q26.2;q21q26.2) previously defined by chromosome analysis. The unblinded results indicated abnormal RPN1/EVI1 fusion results in 30 (97%) of 31 samples from the inv(3)(q21q26.2) group including seven bone marrow samples for which chromosome analysis was unsuccessful or failed to detect an inv(3)(q21q26.2). Abnormal FISH results were detected in 14 (88%) of 16 samples with t(3;3)(q21;q26.2) and in the sole sample with an ins(3;3)(q26.2;q21q26.2). All 30 negative controls were normal and were used to establish a normal cutoff of 0.6% for the typical abnormal D-FISH signal pattern. Overall, this D-FISH assay was more accurate than chromosome analysis and based on the normal cutoff of 0.6%, this assay can be used for minimal residual disease detection and disease monitoring in patients with RPN1/EVI1 fusion.
authors.affiliation: Department of Laboratory Medicine and Pathology, Division of Laboratory Genetics, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905, USA.
authors.forename: Brandon M
authors.initials: BM
authors.lastname: Shearer
authors.forename: William R
authors.initials: WR
authors.lastname: Sukov
authors.forename: Heather C
authors.initials: HC
authors.lastname: Flynn
authors.forename: Ryan A
authors.initials: RA
authors.lastname: Knudson
authors.forename: Rhett P
authors.initials: RP
authors.lastname: Ketterling
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001854:Bone Marrow Cells / Q000648:ultrastructure*; D007446:Chromosome Inversion; D022202:Chromosomes, Artificial, Bacterial; D002893:Chromosomes, Human, Pair 3 / Q000235:genetics* / Q000648:ultrastructure; D015342:DNA Probes; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D015470:Leukemia, Myeloid, Acute / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D016254:Mutagenesis, Insertional; D009190:Myelodysplastic Syndromes / Q000235:genetics*; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D016037:Single-Blind Method; D014178:Translocation, Genetic; D055815:Young Adult
chemical_list: D015342:DNA Probes; D015514:Oncogene Proteins, Fusion; C481798:RPN1-EVI1 fusion protein, human