Elevated mRNA and protein expression levels of HSPB1 were identified in doxorubicin-resistant breast cancer cells (MDA-MB-231/DOX, 231/DOX) compared with parental cells (MDA-MB-231, 231) (Fig. 3A, B), indicating its promoting role in doxorubicin resistance. This evidence concerns the gene HSPB1 and breast cancer.