Although, our MRP7-transfected cells had only low level of resistance to paclitaxel compared to ABCB1-transfected cells [22,43], it had been reported that the gene expression levels of MRP7 was much higher than that of ABCB1 in both paclitaxel-resistance and vinorelbine-resistance NSCLC (nonsmall cell lung cancer) cell lines [31,44]. Here, ABCB1 is linked to lung cancer.