SF3B1 and chronic myelogenous leukemia, BCR-ABL1 positive: In our attempt to study the molecular and cellular defects due to SF3B1 mutation, we observed that introduction of the hotspot mutation in K562 cells, a continuously growing cell line derived from chronic myelogenous leukemia in terminal blast crises widely used as a model for myeloid malignancies, resulted in an increased frequency of giant cells in multiple clones derived from mutant cells but not in wild-type clones.