AHR and breast cancer: We have also demonstrated that 10-Cl-BBQ (3; 10-chloro-7H-benzo[de]benzo[4,5]imidazo[2,1-a]isoquinolin-7-one) (Figure 1), a known AhR ligand, is up to 150-fold selective in targeting certain breast cancer cell lines compared with normal cells or other tumour types (Baker et al., 2021a; Elson et al., 2023).