The decrease in EGFRL858R+ cells at 3 months postinduction observed with wildtype (WT) A3B was no longer observed in the enzyme inactive A3B mouse model (E(CAG)A3BE255A) compared with E control mice (Fig. 1h–j), suggesting that the increase in tumor cell death with A3B expression is at least in part due to the enzymatic activity of A3B. The gene discussed is APOBEC3B; the disease is neoplasm.