Chronic myeloid leukemia (CML) develops due to reciprocal translocation between chromosomes 9 and 22, leading to fusion between BCR and ABL1 genes and formation of fusion BCR-ABL1 gene and, finally, expression of constitutively active BCR-ABL1 kinase [7]. The gene discussed is ABL1; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.