PDGFRA and gastrointestinal stromal tumor: Imatinib was originally designed for breakpoint cluster region-Abelson murine leukemia viral oncogene (BCR-ABL) translocation in chronic myeloid leukemia and has subsequently shown to be effective against KIT and PDGFRA tyrosine kinases in GIST (4).Although more than 80% of patients with GIST can benefit from imatinib, many patients develop imatinib resistance after treatment.