BRCA1 and breast cancer: EZN-2208 (PEG-SN38) was found to overcome the ATP-binding cassette superfamily G member 2 (ABCG2)-mediated topotecan resistance by increasing the DNA damage repair in breast cancer 1 (BRCA1)-deficient mouse mammary tumors [137,138], while chetomin blocked the reprogramming of tumor metabolism in human malignant glioma cells to prevent hypoxic radioresistance [139].