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Objective – To measure the expression of micro RNA 19b in peripheral blood leukocytes of newly diagnosed patients of Chronic Myeloid Leukemia and study the effect of standard care with Imatinib Mesylate on the expression level of above miR.
Study design – Hospital based Case-Control study.
Setting – Department Of Biochemistry, Maulana Azad Medical College, New Delhi, Department Of Pathology, MAMC, New Delhi, Department of Medicine, LNJP Hospital, New Delhi.
Subjects – 35 newly diagnosed CML cases in chronic phase of disease and 35 age and sex matched healthy controls.
Methods – The expression of microRNA 19b in peripheral blood mononuclear cells (PBMCs) of 35 CML cases in chronic phase, in comparison to 35 age and sex matched healthy control subjects was carried out. RNA was extracted from PBMCs of both CML patients and controls using Trizol reagent. Expression studies were performed by SYBR green based qRT-PCR and results were expressed as mean fold change. Expression of miR-19b was measured on two occasions i.e. in newly diagnosed untreated CML patients, and after 6 months of therapy with Imatinib.
Result – The expression of miR-19b in PBMCs of untreated CML patients was up regulated with respect to healthy control subjects at statistically significant levels (p<0.001). A re-evaluation of miR19b levels after six months treatment with Imatinib, revealed statistically significant down regulation of expression ,compared to the pre-therapy status(p <0.001).
Conclusion – The miR-19b functions as an oncomir in the pathogenesis of CML.The consistent down regulation of miR-19b expression in CML patients after Imatinib therapy, suggests that miR-19b could be a downstream component of BCR-ABL tyrosine kinase signaling pathway. The role of miR-19b in persistence of leukemic stem cells after theray with TKIs, needs to be further dissected.