ABL1 and leukemia: The chimeric BCR-ABL proteins constitutively possess tyrosine kinase activities which are postulated to be responsible for the development of leukemia via activating the Ras and mitogen-activated protein kinase pathway (RAS-MAPK), Janus-kinase (JAK)-signal transducer and activator of transcription pathways (JAK-STAT), and bcl-2/Bad/Bcl-xL anti-apoptosis signal pathway to promote cell proliferation, antiapoptosis, and genomic instability [1-3].