Altered Expression of MicroRNAs in the Bone Marrow of Multiple Myeloma Patients and their Relationship to Cytogenetic Aberrations

Background: Multiple Myeloma (MM) is a complex hematologic malignancy, driven by several genetic and epigenetic alterations. MiRNAs as biomarkers have become a rapidly growing research area in the last decade. Aim: The aim was to study the expression pattern of selected miRNAs and to explore the impact of cytogenetic aberrations in MM patients for therapeutic tools. Patients and Methods: Forty Egyptian adult patients were selected for the study with symptomatic newly diagnosed MM disease. Bone marrow samples were collected to investigate twelve miRNAs selected according to their relation to the most common cytogenetic aberrations with relevant prognostic value. The relative expression of the selected miRNAs was determined using a real-time PCR technique. Fluorescence In Situ Hybridization (FISH) technique was performed for cytogenetic analysis. Results: Eight miRNAs were down-regulated [miR-15a (p<0.001), miR214-3p (p<0.001), miR135b (p<0.001), miR19a-3p (p<0.001), miR19b-3p ((p=0.026), miR30e-5p (NS), miR133a (NS), miR146a- 5p (p<0.001)]. Four miRNAs were up-regulated [miR99b-5p (p=0.028), miR125a-3p (p=0.004), let7b- 5p (p<0.001), let7c-5p (p<0.001)]. Significant relation was observed between positive 14q32 rearrangement using the break apart re-arrangement probe for 14q32.33 locus and lower expression levels of miR15a (p= 0.014), 214-3p (p=0.046), 99b-5p (p=0.014), 146a-5p (p=0.041). A higher expression level of miR30e-5p was significantly related to positive 14q32 rearrangement. Conclusion: Deregulated miRNAs were identified and the association with 14q32 rearrangement and MM pathogenesis has been determined.