Although the development of imatinib, a tyrosine kinase inhibitor (TKI) has redefined the management of CML7, the resistance to imatinib occurs in 20~30% of CML patients and is commonly attributable to point mutations in the BCR-ABL kinase domain8, 9. The gene discussed is BCR; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.