The current guideline for axillary surgery recommends the omission of SNB in select patients who are postmenopausal and ≥50 years of age and in those with negative findings on preoperative axillary ultrasound for grade 1–2 small (≤2 cm), hormone receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancers and who underwent breast-conserving therapy (11). Here, ERBB2 is linked to breast cancer.