These transporters are present in more than 50% of cancer-presenting MDR phenotypes or can be induced by chemotherapy [140] and encoded by multidrug resistance protein 1 gene (MDR1 or ABCB1) for the p-glycoprotein or the ABCG2 gene for the breast cancer resistant protein (BCRP) [141]. This evidence concerns the gene ABCG2 and cancer.