A pooled analysis from four prospective neoadjuvant clinical trials involving 1098 HER2-low and 1212 HER2-negative primary breast cancer patients reported that the pCR rate was significantly lower in the HER2-low group compared to the HER2-negative group (29.2% vs. 39.0%, p=0.0002), long-term outcomes, however, were significantly better in HER2-low patients (3-year DFS: 83.4% vs. 76.1%, p=0.0084; 3-year OS: 91.6% vs. 85.8%, p=0.0016) (18). This evidence concerns the gene ERBB2 and breast cancer.