PGP and breast cancer: Previously we found flucloxacillin conjugating in the tight actin bundles after treating HepaRGs with increasing concentrations of flucloxacillin, suggesting localization at BC, which was further confirmed by staining for MRP2 and P-gp within BC regions (Waddington et al., 2020a) Prolonged flucloxacillin treatment of HepaRGs has resulted in significant BC dilation, consistent with published findings (Burban et al., 2017).