Buggi et al. reported that ER status was discordant in 4.4%, PR status was discordant in 15.9%, and HER2 status was discordant in 9.7% of patients with multiple breast cancers, resulting in a total of 12.4% of patients not receiving the correct adjuvant treatment due to heterogeneity [21]. Here, ERBB2 is linked to breast cancer.