GATA3 and acute lymphoblastic leukemia: Expression of GATA3 which is an important downstream event of Notching signaling necessary for the production of early T-lineage progenitor cells.[26] GATA3 mutation sequencing data was identified as one of the recurring somatic genetic abnormalities in early T-cell precursor acute lymphoblastic leukemias (ALL) with a frequency of approximately 10% (6 of 64 cases).