To address all these questions, we conducted this retrospective study based on medical records of female breast cancer from one general referral hospital in southwest China, based on which, we also investigated the epidemiological characteristics of HER2-low tumors comparing with those with positive and negative HER2 expression and explored the possible influential factors that might be associated with the discordance between CNB and SEB. Here, ERBB2 is linked to breast carcinoma.