miRNAs expression profiling in circulating lymphocytes of CML patients after imatinib discontinuation

Some chronic myeloid leukemia (CML) patients with complete molecular response (CMR) are considered able to sustain the CMR after imatinib discontinuation (STOP-IM). Mahon et al. reported that among patients with a CMR lasting at least 2 consecutive years, the CMR was sustained in 41% after imatinib discontinuation. To more appropriately identify patients who can safely discontinue imatinib, we assessed the miRNA profiles of CML patients. We compared CML patients who sustained CMR for more than 6 months after discontinuation of imatinib (STOP-IM group) with those who were receiving imatinib with CMR (currently called as UMD: undetermined minimal disease), and with healthy volunteers (controls). Peripheral blood mononuclear cells (PBMCs) were harvested form 10ml of whole blood. Isolation of total RNA was performed using the mirVana PARIS kit (Ambion, Austin, TX, USA). The expression profile of miRNAs was determined using the Human Taqman miRNA Arrays A (Applied Biosystems). RNU6B were used as acontrol. QRT-PCR was carried out on an Applied Biosystems 7900HT thermal cycler using the manufacturer’s recommended program. Finally, all the raw data from each array was run on Data Assist Software ver.3.1 (Applied Biosystems).