NOTCH1 and B-cell chronic lymphocytic leukemia: A study of 452 CLL cases and 54 patients with monoclonal B-lymphocytosis, a precursor disorder, comprised a comprehensive evaluation of recurrent mutations in non-coding regions and found recurrent alterations in the 3′ region of NOTCH1, which cause aberrant splicing events, increase NOTCH1 activity, and result in a more aggressive disease [33].