Sustained specific immune responses were commonly observed in patients with long-term CR, whereas either decreased number or absence of NPM1-mutated-specific T cells strongly correlated with leukemia relapse, suggesting an inverse correlation between the kinetics of MRD and anti-leukemic specific T cells, as observed in BCR-ABL-positive acute lymphoblastic leukemia patients [13–15]. This evidence concerns the gene NPM1 and acute lymphoblastic leukemia.