TKI resistance is defined as "failure" in the evaluation of CML treatment response, referring to the definition of ELN failure in 2020 recommendations, with BCR-ABLIS > 10% if confirmed within 1-3 months, BCR-ABLIS > 10% at 6 months of TKI treatment, BCR -ABLIS > 1% at 12 months of treatment, or BCR-ABLIS >1% at any time after 12 months of treatment, with resistance mutations, the emergence of high-risk additional chromosome abnormalities (ACA)10, 11. The gene discussed is BCR; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.