DPP4 and chronic myelogenous leukemia, BCR-ABL1 positive: Apart from being detected at diagnosis, these cells are strikingly enriched after TKI therapy (Warfvinge et al., 2017), a finding since confirmed in a transgenic mouse model (Shah et al., 2023), and in clinical observations documenting the long-term persistence of CD26+ cells in CML patients (Pacelli et al., 2023).