NOTCH1 and acute lymphoblastic leukemia: To validate the dual role of NRARP in human primary T-ALL cells we exposed primary or patient-derived xenograft (PDX) T-ALL cells, classified according to their NOTCH1 mutational status/levels of NICD1 (Supplementary Fig. S7, A, B) [28], to NRARP recombinant protein (rNRARP) (Supplementary Fig. S7C, D).