APOB and cancer: In most cancer types with kataegis (localized hypermutation), the mutational signatures indicate an association with apolipoprotein B messenger RNA-editing, enzyme-catalytic, polypeptide-like 3 (APOBEC3) enzymes (DNA cytidine deaminases that remove the amino group from a cytosine, converting it to uracil), and show strong enrichment of C-to-T transitions [20].