ABCG2 and neoplasm: To test this hypothesis, the toxicity of the longer chain MILs was examined in the mouse cardiomyocyte HL-1 cell line in the absence and presence of the BCRP inhibitor Ko143 or p-glycoproteins inhibitor cyclosporin A. The HL-1 cell line is a mouse proliferative atrial cardiomyocyte that originated from the SV40-transformed tumour cell line AT-1.