With the discovery of the Philadelphia chromosome [6,7] and the development of the BCR-ABL tyrosine kinase inhibitor (TKI) imatinib in chronic myeloid leukemia (CML) at the turn of the twenty-first century [8], precision oncologic approaches were realized in the treatment of HRMNs. The gene discussed is ABL1; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.