ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: On the other hand, BCR-ABL transduction-transplantation models [3, 6, 35, 36] and transgenic CML models [37–39], including conditional transgenic CML mice models, in which BCR-ABL expression was targeted to stem cells [40, 41], suggest that BCR-ABL is sufficient to initiate a rapidly fatal CML-like myeloproliferation.