The tandem CAG, CTG and CGG repeats in coding regions or UTRs in many protein-coding genes (targeted C residues underlined) will thus provide rich targets for cytosine deamination if the AID/APOBEC deamination events become dysregulated and go ‘off target’ as appears to occur across the genome in cancer (Lindley, 2013; Lindley and Steele, 2013; Lindley et al., 2016). This evidence concerns the gene AICDA and cancer.