NOTCH1 and acute lymphoblastic leukemia: Although PEST domain mutations in Notch1 protein mainly regard oncogenic events in T-ALL [57], around 13% of TNBC exhibits in-frame deletions of Notch1 exons 21-27, which disrupt the NRR and HD domains, thus leading to upregulation of its pathway caused by either ligand-independent receptor activation or N1ICD half-life extension [40].