NOTCH1 and B-cell chronic lymphocytic leukemia: In monoclonal B-cell lymphocytosis (MBL, defined by <5000 CLL-phenotypic cells per μl peripheral blood) (10), NOTCH1 mutations were found in 11% of cases compared to a frequency of 13% observed in early stage CLL (Binet A) not requiring treatment (frequencies in MBL and early stage CLL did not significantly differ when assessed within the same clinical trial, NCT00917450; p=0.6046 as inferred by Fisher’s exact test) (10).