ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: Due to alternative splicing, two major breakpoints are known as b3a2 and b2a2, and both mRNAs are translated into p210 BCR-ABL protein (Yaghmaie et al., 2008; Mir et al., 2015), and contribute to most of the classical CML phenotype.