Given the negative correlation between miR-155 and SMAD5 and TGF-βR2, we transfected an antagomiR of miR-155 into the CD34+ CML cells to evaluate the miR-155 knock-down on the expression levels of SMAD5 and TGF-βR2. The gene discussed is CD34; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.