Using this more affordable and rapid strategy, recent studies have determined the prognostic impact of TP53 subclones.13 In addition, the status of ATM, NOTCH1 and SF3B1, also recurrently mutated in CLL, have been associated with impaired overall and treatment-free survival.14, 15, 16 Nevertheless, a comprehensive high-throughput sequencing study of these variants, assessing their clinical relevance, in the context of both traditional and newer factors, is lacking. This evidence concerns the gene NOTCH1 and B-cell chronic lymphocytic leukemia.