An exciting possibility for patients with cN0 disease treated with NAC is the potential to omit axillary surgery altogether, based on data showing very low rates of pathological nodal involvement (<2%) in patients with cT1–2 cN0 HER2+ breast cancer or TNBC who achieve a breast pCR79,80, as shown in Table 3. This evidence concerns the gene ERBB2 and breast cancer.