APOBEC3B and cancer: Here, we found that rs12628403 reduces APOBEC3B-like mutagenesis specifically in cancer types with low levels of APOBEC mutagenesis (βlow = −0.50, Plow = 1 × 10−8; βhigh = 0.17, Phigh = 0.2), and increases APOBEC3A-like mutagenesis in cancer types with high levels of APOBEC mutagenesis (βhigh = 0.44, Phigh = 8 × 10−4; βlow = −0.21, Plow = 0.02).