USP18 and chronic myelogenous leukemia, BCR-ABL1 positive: Bone marrow cells harvested from USP18−/− mice and transfected with BCR‐ABL prior to transplantation into wild‐type recipient mice developed a CML‐like state in only 40% of cases, whereas all mice transplanted with USP18+/+ BCR‐ABL expressing cells developed disease (Yan et al., 2007).