MAPK3 and chronic myelogenous leukemia, BCR-ABL1 positive: Interestingly, these Nilotinib-resistant CML cells were shown to display constitutive activation of Lyn a situation that is closed to the one observed in our TKI-resistant K562 cell lines where the Fyn but not Lyn tyrosine kinase is constitutively activated and participates to persistent ERK1/2 activation [9, 10, 20].