Compared with healthy marrow donors, chronic phase CML (CML-CP) patients had lower expression of NR4A1 but not NR4A3. This result is compatible with the idea that downregulation of NR4A1 confers a proliferation advantage (class I aberration), resulting in a myeloproliferative presentation. This evidence concerns the gene NR4A3 and chronic myelogenous leukemia, BCR-ABL1 positive.