CASP6 and chronic myelogenous leukemia, BCR-ABL1 positive: Because we found that USP15 downregulation led to decreased apoptosis in CML cells by lowering the level of Caspase-6 protein, we sought to know whether the expression of USP15 is suppressed in CML cells by a microRNA that targets 3′-untranslated region (3′-UTR) of USP15 mRNA.