AGR2 and breast cancer: The outcome suggests that breast cancer patients with relatively AGR2 low expression may be more suitable for the treatment of immunotherapy, while the AGR2 high expression subgroup can firstly inhibit the expression of AGR2 by monoclonal antibody and transform poor immunogenic (cold) tumors into highly immunogenic and well-infiltrated (hot) tumors, which provides a personalized immunotherapy strategy for breast cancer based on AGR2.