In CML, the identification of the BCR-ABL1 fusion gene, resulting from the t(9;22)(q34;q11) translocation known as the Philadelphia chromosome (Ph) [1,2], has been a groundbreaking discovery that led to the development of targeted therapies like tyrosine kinase inhibitors (TKIs), drastically improving patient outcomes [3]. The gene discussed is ABL1; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.