It is yet to be determined in ATMKO T-LBLs if functional inactivation of PTEN is required for lymphomagenesis or is a mutational hit selected for post-transformation, but studies of primary human T-ALL samples using single-cell DNA amplicon sequencing of diagnosis-remission paired samples and xenografts have suggested that PTEN loss may be a relatively late event associated with subclonal evolution and relapsed disease [44–46]. The gene discussed is PTEN; the disease is acute lymphoblastic leukemia.