ABCG2 and cancer: CSCs present a tough challenge in elimination due to their inherent resistance to anti‐cancer drugs.[50] Notably, overexpression of BCRP, an efflux transporter that actively expels various anti‐cancer drugs from the cells, has been widely recognized for conferring chemoresistance in CSCs.[51] The protein (Figure S3A, Supporting Information), mRNA (Figure S3B, Supporting Information), and Hoechst33342 efflux activity (Figure S3C, Supporting Information) of BCRP in MCF7 cells were induced by DEHP.