ERBB2 and neoplasm: Various clinical trials [1,2,3] have shown that the use of NAC provides opportunities for certain patients, such as systemic control for patients with locally advanced tumours, improvement in conditions for a conservative management of T3 tumours and for women with small breasts, and as a tumour sensitivity test to drugs, especially for those subtypes with a more aggressive biological component, such as triple negative and human epidermal growth factor receptor 2 (HER2) overexpression.