These features, together with the lack of eosinophilia, basophilia or monocytosis, and the absence of BCR-ABL transcripts, distinguish CNL from chronic myeloid leukemia (CML), atypical CML and chronic myelomonocytic leukemia, as defined by the French-American-British (FAB) Cooperative Group (2). This evidence concerns the gene BCR and chronic myelogenous leukemia, BCR-ABL1 positive.