ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: To test this idea, we first examined whether BCR-ABL-expressing LSK− cells contain more apoptotic cells than LSCs in bone marrow of CML mice, and found that apoptotic cells in the GFP+LSK− cell population were two-fold higher than those in the GFP+LSK cell population (Fig. 6A).