To evaluate this hypothesis, we analyzed the effects of Notch inhibition on the enrichment of both active H3K27ac and repressive H3K27me3 epigenetic marks and on the occupancy by the related histone-modifying factors at the NOTCH3 gene in Notch3-dependent TALL-1 and Notch1-dependent MOLT3 T-ALL cells. The gene discussed is NOTCH1; the disease is acute lymphoblastic leukemia.