In a first, large cross-sectional study of more than 400 CML patients at diagnosis, on TKI treatment or in TFR [44], they found that CD26 expression could be detected by multiparametric flow cytometry analysis of PB CD45+/CD34+/CD38− cells not only (as expected) at diagnosis, but also in patients with DMR, as well as in a significant proportion (66%) of patients in TFR. Here, DPP4 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.