To identify regulators of endocrine resistance in breast cancer, we integrated four GEO datasets comprising tamoxifen‐resistant cell line models and clinical samples from neoadjuvant therapy nonresponders, identifying ARL3 as a top‐ranked candidate through cross‐dataset analysis of differentially expressed genes (FDR <0.05, fold‐change >1, Figure1A). This evidence concerns the gene ARL3 and breast cancer.