CLL with MYD88 L265P mutation represented a distinct group of patients that were younger and associated with several favorable prognostic factors, including lower levels of β2-microglobulin, lower frequency of CD38 and ZAP70 expression, and higher frequency of mutated IGHV. CLL with MYD88 L265P mutation was also associated with isolated deletion of 13q14.3, a lower frequency of deletion 11q22.3, and a lower frequency of NOTCH1 and SF3B1 mutations. This evidence concerns the gene ZAP70 and B-cell chronic lymphocytic leukemia.