The tumor HER2 status has been linked to the probability of achieving complete pathological response (pCR) to an anti-HER2 treatment (Trastuzumab or double blocking with Trastuzumab-Pertuzumab) in a neo-adjuvant setting, with the HER2/CEP17 ratio having a predictive value on its own: patients with weakly amplified carcinomas have low rates of pCR [10,11]. The gene discussed is ERBB2; the disease is carcinoma.