The study involved down-regulation of Notch1 in T-ALL cell lines (CCRF-CEM cells and MOLT-4 cells) through treatment with gamma-secretase inhibitor (GSI) as well as the modulation of Asb2 in CCRF-CEM cells and MOLT-4 cells through transduction with lentivirus carrying Asb2 or Asb2-shRNA. This evidence concerns the gene NOTCH1 and acute lymphoblastic leukemia.