Herein, we reported that TRIM25 directly interacted with BRD7, and promoted the degradation of BRD7 through the ubiquitin-proteasome mediated pathway in breast cancer cells as an E3 ligase, and then activated YB1/Bcl-2 transcription axis, thus promoting the malignant progression and chemotherapy resistance of PTX of breast cancer in vitro and in vivo. The gene discussed is YBX1; the disease is breast carcinoma.