ERBB2 and breast cancer: Kaplan–Meier curves showed that HER2-low breast cancers had significantly better LRFS than HER2-zero tumors (Bonferroni corrected p = 0.006), but there was no statistically significant difference between the HER2-low and HER2-positive tumors (Bonferroni corrected p = 0.531) or between the HER2-zero and HER2-positive tumors (Bonferroni corrected p = 0.153; Figure 1A).