Remarkable increases in two important ABC transporters, MDR1 and BCRP, were observed in the BTZ-resistant U-2 OS cells at both mRNA and protein levels compared with that in their parental cells, consistent with prior reports of MDR1 overexpression as the most notable change in BTZ-resistant cancer cells 33-35 (Figure 2D-E). Here, ABCB1 is linked to cancer.