For example, siRNA-mediated FTH1 knockdown decreased the LD50 of carmustine from 100 to 40 μM in U-251 glioblastoma cells, and similar depletion of FTH1 and FTL by miR-200b lowered the IC50 of doxorubicin from 20 to <5 μM in MDA-MB-231 breast cancer cells (81, 140). Here, FTH1 is linked to breast cancer.