Microarray testing as an efficient tool to redefine hyperdiploid paediatric B-cell precursor acute lymphoblastic leukaemia patients

Abstract

The aim of our study was to characterize genetic alterations in a cohort of paediatric patients with B-cell progenitors (BCP-ALL) and a hyperdiploid karyotype. In our study, we analysed 55 childhood hyperdiploid BCP-ALL patients using single nucleotide polymorphism (SNP) microarray testing. The group consisted mostly of patients with the modal number of chromosomes between 54 and 58 (34 cases). Within this group, Trisomy 4 and Trisomy 10 (30 cases) were the most frequent cases. Additionally, a total of 93 structural abnormalities mainly affecting chromosomes 1, 6, 9, 12, and 17 as well as 68 copy number alterations (CNAs) were identified. The microarray testing revealed a loss of ETV6, IKZF1, CDKN2A/CDKN2B, PAX5, and RB1. Moreover, chromosomal abnormalities resulting in the loss of heterozygosity (LOH) were also observed. Currently, patients with hyperdiploidy constitute a genetically heterogeneous group, and therefore, it is insufficient to rely only on banding cytogenetic analysis for the identification of hyperdiploid karyotype. Microarray testing has been proven an effective and satisfactory tool for the analysis of molecular karyotypes and to redefine the prognostic criteria in hyperdiploid patients.