APOBEC3B and cancer: The report that A3B expression is associated with adverse outcomes in oestrogen receptor-positive (ER+) BRCA would be consistent with this hypothesis (figure 3) [141] as well as the analysis of 30 human cell lines, including BRCA cell lines, from which expression levels of the A3B gene were associated with resistance to anti-cancer drugs such as vinblastine, topotecan, paclitaxel, mitoxantrone, mitomycin C, etoposide and doxorubicin (figure 3) [145].