The management of patients with chronic myeloid leukemia (CML) was transformed with the implementation of tyrosine kinase inhibitors (TKIs) to target the breakpoint cluster region-Abelson murine leukemia viral oncogene homolog (BCR-ABL), which is responsible for the disease. The gene discussed is ABL1; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.