Recently, our research team reported a high discordance rate of HER2 low status between paired core needle biopsy (CNB) and surgical excision sample (SES) in early-stage breast cancer patients not receiving NAT, which emphasized the importance of exploring the inconsistency of HER2-low expression from primary breast cancer to matched residual disease in neoadjuvant setting [25]. This evidence concerns the gene ERBB2 and breast cancer.