AID activity was the most ubiquitous according to the enzyme characteristic signature in various cancer types, whereas the APOBEC1, APOBEC3A, APOBEC3B, and APOBEC3G signatures were detected less frequently, although their signatures were stronger, most notably in breast, lung, cervix, skin, and bladder cancer (Figure 2). The gene discussed is APOBEC3A; the disease is cancer.