ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: Therefore, monitoring of the persistence specific surrogate disease biomarkers in CML (Ph chromosome, BCR-ABL1 fusion gene, and BCR-ABL1 mRNA) is very important during a treatment to prevent disease relapse as well as to establish the end-point of therapy (Jabbour and Kantarjian, 2014).