Double inv(3)(q21q26.2) in acute myeloid leukemia is resulted from an acquired copy neutral loss of heterozygosity of chromosome 3q and associated with disease progression

Double inv(3)(q21q26.2) in acute myeloid leukemia is resulted from an acquired copy neutral loss of heterozygosity of chromosome 3q and associated with disease progression

Molecular Cytogenetics, August 2015

26300976

Jun Gu, Keyur P. Patel, Bing Bai, Ching-Hua Liu, Guilin Tang, Hagop M. Kantarjian, Zhenya Tang, Ronald Abraham, Rajyalakshmi Luthra, L. Jeffrey Medeiros, Pei Lin, Xinyan Lu

Acute myeloid leukemia (AML) with inv(3)(q21q26.2)/t(3;3)(q21;q26.2) is a distinct clinicopathologic entity with a poor prognosis. However, double inv(3)(q21q26.2) is extremely rare in AML. We report here 3 cases analyzed by oligonucleotide microarray comparative genomic hybridization (aCGH) and single nucleotide polymorphism (SNP). Clinicopathologic, cytogenetic and molecular findings were correlated with clinical outcome to better understand the entity. The study group included one man and two women at 56-74 years of age. The AML arose from myelodysplastic syndrome in one patient and from chronic myelomonocytic leukemia in another patient. Monosomy 7 was found as additional cytogenetic finding in one patient. One patient had a single inv(3) in the initial clone and acquired double inv(3) as part of clonal evolution. EVI1 (MECOM) rearrangement was confirmed using metaphase/interphase fluorescence in situ hybridization (FISH). Microarray (aCGH + SNP) data analysis revealed that the double inv(3) was a result of acquiring copy neutral loss of heterozygosity of chromosome 3q: arr[hg19] 3q13.21q29(10,344,387-197,802,470)x2 hmz, spanning ~ 94.3 Mb in size. Mutational profiling showed a PTPN11 mutation at a low level (~10 %) in one patient and wild type FLT3 and RAS in all patients. No patients achieved cytogenetic remission and all died with an overall survival (OS) of 23, 12 and 5 months, respectively. Double inv(3) is a result of acquired copy neutral loss of heterozygosity, a somatic repair event occurring as a part of mitotic recombination of the partial chromosome 3q. The double inv(3) in AML patients is highly associated with a rapid disease progression.