Imatinib, targeting BCR-ABL tyrosine kinase, was approved to used for chronic myelogenous leukemia harboring Philadelphia chromosome-positive (Ph+) and gastrointestinal stromal tumors (GIST) with C-kit mutant gene in 2001 by FDA. The gene discussed is ABL1; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.