NQO1 and infection: Upregulating the expression of Nrf2 in MCF-7 cells (which exhibit relatively low HBXIP and Nrf2 expression compared with MDA-MB-436 cells9 (Supplementary Fig. 1A)) by infection with LV-Nrf2 lentivirus or treating cells with H2O2 to activate Nrf2 led to significant upregulation of HBXIP and NQO1 protein expression (Fig. 4A, left panel).