NOTCH1 and B-cell chronic lymphocytic leukemia: Similar effects of GSI, used alone or in combination with fludarabine, were obtained in the high-risk CLL subset of patients carrying a mutated NOTCH1. These cells proved to be sensitive to PF-03084014, a non-competitive and reversible GSI, with inhibition of the constitutive activation of the pathway and modulation of apoptosis, as well as migration of leukemic cells (69).