These results revealed that some of the above-mentioned DEGs associated with chromatin accessibility changes, such as FOXA1, GATA3 and GSTP1, played a critical role in the development of doxorubicin resistance in breast cancer cells, and might be important indicators for judging the prognosis or a therapeutic target in breast cancer patients treated with doxorubicin. Here, GSTP1 is linked to breast cancer.