ER‐α expression levels are an important clinical biomarker used to predict TAM treatment outcomes, with a lack of ER‐α leading to TAM resistance and TNBC.[3, 22] Here, we found that TRIM4 serves as a predictor of breast cancer and that the loss of TRIM4 conferred TAM resistance in ER‐α‐positive breast cancer. This evidence concerns the gene ESR1 and breast cancer.