They were previously demonstrated to increase fluorescent dye accumulation in human ABCB1 gene-transfected mouse lymphoma cells and, to much lesser extent, in colon carcinoma Colo320/MDR1-LRP cells, but not in ABCC1 expressing breast cancer (HTB-26/MRP1) and stomach cancer (257P/MDR) cells, which was attributed to their specific interactions with the ABCB1 transporter [15]. Here, ABCB1 is linked to breast cancer.