BCR and chronic myelogenous leukemia, BCR-ABL1 positive: Then we constructed two shRNA expression plasmids targeting the BCR-ABL fusion gene, a vital marker molecule of chronic myelogenous leukemia (CML) (Quintas-Cardama and Cortes, 2009; Salem et al., 2017), encoding a continuously activated tyrosine kinase activity that leads to overproliferation (Reckel et al., 2017).