Pathologic complete response (pCR) rates are highest in human epidermal growth factor receptor 2-positive (HER2+) and triple negative (TN) subtypes (40–89%), whereas lower rates are observed in hormone receptor-positive (HR+)/HER2-negative (HER2−) breast cancer (10–15%).3–11 As it is questionable whether surgical resection contributes to local control in patients with pCR, less invasive techniques than surgery to assess pCR in patients who underwent NST would be preferable. The gene discussed is ERBB2; the disease is breast cancer.