ATM and B-cell chronic lymphocytic leukemia: In this regard, Landau et al. (2013) identified three driver mutations as clonal—MYD88, trisomy 12, and hemizygous del(13q)—appearing in the CLL-originating cell, while other mutations appeared later during the neoplastic development, such as mutations in the ATM, TP53, RAS, and SF3B1 genes, and were usually associated to poor prognosis [27].