The latest World Health Organization (WHO) classified MPNs into chronic myeloid leukemia (CML) BCR::ABL1+, polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF) (Arber et al., 2016). The gene discussed is BCR; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.