That there was no correlation between IC50 values of artesunate and mRNA expression of the multidrug resistance-conferring ABCB1 gene (coding for P-glycoprotein efflux pump) in the National Cancer Institute cancer cell lines and that artesunate is similarly active towards cell lines which over-expressing MDR1/P-glycoprotein [54-56] indicate that artesunate isn't a substrate for these chemotherapy defeating elements. Here, ABCB1 is linked to cancer.