To test this, two TKI-resistant cell lines derived from the myeloid BP-CML cell line KCL-22 were identified; the first was developed after continual sublethal exposure to nilotinib and carries the BCR::ABL1 mutation T315I (KCL-22 T315I) [37], while the second was established after continual sublethal exposure to ponatinib (KCL-22 PonRes) [38] and developed resistance without BCR::ABL1 kinase mutation. This evidence concerns the gene ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive.