With increasing research on the immune microenvironment and evidence of clinical relevance of tumor-infiltrating lymphocytes (Tils) in breast cancer, Tils have shown potential predictive value for prognosis, especially in triple-negative and HER2-overexpressing breast cancer, with results showing a positive correlation between the degree of Tils infiltration and prognosis (5, 6). This evidence concerns the gene ERBB2 and breast cancer.