Affymetrix SNP array data for acute lymphoblastic leukemia samples

In precursor B-cell acute lymphoblastic leukemia (ALL), whole chromosome uniparental isodisomy (wUPD) occurs almost uniquely in the high hyperdiploid (51-67 chromosomes) (HH) subtype. Comparison of 26 HH with wUPD with 31 with noUPD, showed a higher modal number of chromosomes and gains of 5+ in wUPD. Mutations in genes within epigenetic pathways with upregulation of genes involved in cellular response to stress and stimuli, and mutations in RAS/RTK pathways and upregulation of genes in RNA Polymerase III pathway were seen in wUPD and noUPD respectively. Though overall outcomes were similar in patient with and without wUPD, those with noUPD were more likely to have residual disease after treatment. Differential gene expression between the two groups showed upregulation of genes involved in thiopurine drug resistance in wUPD. Genome-wide differences between HH ALL with and without UPD identified plausible biological explanations for the heterogeneity in therapeutic response in HH ALL. Copy number analysis of Affymetrix CytoscanHD SNP arrays was performed for 56 pediatric High hyperdiploid Acute Lymphoblastic Leukemia samples.