Based on a comprehensive literature review, we selected 14 functionally relevant miRNAs involved in the regulation of EMT and anti-tumor immune response and evaluated their clinical significance in primary HER2-positive (n = 22) and HER2-negative (n = 21) breast cancer patients who received neoadjuvant trastuzumab-chemotherapy or chemotherapy alone, respectively (Table 1, Supplementary Table 1). The gene discussed is ERBB2; the disease is breast cancer.