First, in rare cases, BCR-ABL develops mutations that render CML resistant to TKI treatment [12]; second, TKIs based therapies are unable to completely eradicate the disease, due to the resistance of CML stem cells to TKI [13]; third, CML blast crisis, and other Ph+ leukemias such as ALL, are barely unaffected by TKI therapy [14]. This evidence concerns the gene ABL1 and acute lymphoblastic leukemia.