In a previous study aimed to explore the mechanisms underlying NOTCH1 activation in CLL cells devoid of NOTCH1 mutations, we excluded the possibility that genetic lesions of NF-κB regulators or JAGGED1 and JAGGED2 genes were involved in NOTCH1 activation in these leukemic cells (136). The gene discussed is JAG1; the disease is B-cell chronic lymphocytic leukemia.