BCR and acute lymphoblastic leukemia: Then she started to induction chemotherapy with imatinib (400 mg/d), cyclophosphamide, daunorubicin, vincristine and prednisolone referring to the Treatment Guideline for China Adult Acute Lymphocyte Leukemia, and achieved complete response by morphology and immunophenotype, the BCR-ABL gene quantification decreased to 1%, and the chromosomal karyotype returned to normal, but a new gene mutation E255V was detected in the ABL kinase region which was moderately sensitive to dasatinib and resistant to imatinib.