B2M and breast cancer: In conclusion, this study found that knockdown of circ_0058063 increased CDDP-sensitivity and suppressed stem cell biomarkers in BC, and B2M might be the downstream effector gene, and we provided evidences that the circ_0058063/miR-355-5p/B2M axis may serve as the foundation for the development of novel potential therapeutic strategies to enhance CDDP-sensitivity in BC.