PTEN and acute lymphoblastic leukemia: The extensive characterization of the genetic bases of ALL is leading to an attempt of combining MRD with other markers: a pivotal study was carried out by the GRAAL group (130) which evaluated 423 young adults with Ph- ALL in first remission (both B- and T-lineage ALL), demonstrating that a higher risk of relapse was associated with MRD persistence and can be further refined by the presence of IKZF1 deletions in B-lineage ALL, and by the absence of NOTCH1/FBXW7 mutation, and/or by the presence of N/K-RAS mutation and/or PTEN gene alteration in T-cell ALL.