Gene expression analysis of 12 B-cell Chronic Lymphocytic Leukemia samples and 5 CD19+ control samples

Elevated levels of microRNA miR-155 represent a candidate pathogenic factor in chronic B-lymphocytic leukemia (B-CLL). In this study, we present evidence that MYB (v-myb myeloblastosis viral oncogene homolog) is overexpressed in a subset of B-CLL patients. MYB physically associates with the promoter of MIR155 host gene (MIR155HG, also known as BIC, B-cell integration cluster) and stimulates its transcription. This coincides with the hypermethylated histone H3K4 residue and spread hyperacetylation of H3K9 at MIR155HG promoter. Our data provide evidence of oncogenic activities of MYB in B-CLL that include its stimulatory role in MIR155HG transcription. We have studied differentially expressed genes in the whole genome and also in the preselected groups of MYB target genes and miR-155 microRNA predicted targets. This study was intended to investigate differentially expressed genes mRNA in 12 B-CLL patient peripheral blood samples in comparison with 5 CD19+ healthy donor peripheral blood samples.