AICDA and B-cell chronic lymphocytic leukemia: One such study, by Alexandrov et al., analysed 28 CLL WGS and 103 whole-exome sequencing samples and found that CLL mutations comprise three mutational signatures: (i) ageing-related mutations (C>T at CpG mutations due to spontaneous deamination4; signature 1B); (ii) APOBEC signature (signature 2); and (iii) an activation-induced cytidine deaminase (AID)-related signature (signature 9).