The first study included 1378 patients with ERBB2-zero MBC from the MBC registry of the Austrian Study Group of Medical Tumor Therapy and reported a 44% prevalence rate for ERBB2-low MBC,16 whereas a study that used the China National Center Database reported a similar prevalence rate of 43.1%.15 In early BC, a pooled analysis of individual patient’s data from 2310 patients with ERBB2-zero BC who were included in 4 prospective neoadjuvant clinical trials resulted in a prevalence rate of 47.5% for ERBB2-low BC.12 Here, ERBB2 is linked to breast cancer.