Analyses of the clinical characteristics of HER-low breast cancer from four prospective neoadjuvant clinical trials showed that HER2-low breast cancer was significantly associated with a lower number of G3 tumors, lower Ki-67 labeling index, and reduced number of TP53 mutations compared with HER2-IHC 0 breast cancer [18]. The gene discussed is MKI67; the disease is breast carcinoma.