Leonardi et al. demonstrated that the number of positive SLNs, higher ratio of positive SLNs/total SLNs, larger SLN metastasis size, SLN extracapsular extension, and aggressive tumor biology (HER2+ vs. HER2-) remained significant predictors of additional lymph node metastasis in ALND [45]. Here, ERBB2 is linked to neoplasm.