However, seemingly paradoxical, a germline APOBEC3A-APOBEC3B fusion polymorphism causing deletion of A3B is associated with greater risk for breast, ovarian and liver cancer along with an overall increase in mutations present in ΔA3B−/− breast cancers [130,131,132,133,134,135]. The gene discussed is APOBEC3B; the disease is breast carcinoma.