MRP8 is encoded by ARCC11 genes and pumps 5-fluorouracil whereas MXR/BCRP (multixenobiotic resistance and breast cancer resistance proteins, respectively) encoded by ABCG2 genes causes mitoxantrone, topotecan, doxorubicin, daunorubicin, CPT-11, imatinib, and methotrexate resistance [25]. The gene discussed is ABCG2; the disease is breast cancer.