The BCR‐ABL fusion gene is a characteristic cytogenetic change in chronic myeloid leukemia and certain ALL patients, resulting from the fusion of the BCR gene of the long arm of chromosome 22 with the ABL gene of the long arm of chromosome 9 (Kang et al., 2016). The gene discussed is BCR; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.