Our efforts have generated the halogenated aryl hydrocarbon ANI-7 (1; (Z)-2-(3,4-dichlorophenyl)-3-(1H-pyrrol-2-yl)acrylonitrile) and the polyaromatic hydrocarbon NAP-6 (2; (Z)-2-(2-aminophenyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione) (Figure 1) as two molecules displaying more than 500-fold selective targeting of certain breast cancer cell lines compared with normal breast cells or other tumour types via activation of the AhR pathway (Gilbert et al., 2017; Gilbert et al., 2020). Here, AHR is linked to breast cancer.