For example, lack of response to tyrosine kinase inhibition, as measured by log-reduction in BCR-ABL1 transcripts, is now a provisional criterion for accelerated-phase CML in the 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia [28, 29]. Here, ABL1 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.