BCL2L1 and chronic myelogenous leukemia, BCR-ABL1 positive: However, vivo-Morpholino (vMO) antisense oligomers that used to upregulate Bcl-xS expression but decrease Bcl-xL in chronic myeloid leukemia (CML) increased growth inhibition and apoptotic sensitivity of imatinib mesylate-resistant CML cells [5].