Nevertheless, recent retrospective analyses of trastuzumab treated HER2 ≤ IHC2+ advanced gastric adenocarcinomas demonstrated a HER2:CEP17 ratio of >3.69 and a HER2 gene copy number of >7.75 to be positive predictive factors of HER2 targeted therapy survival benefit, underscoring the need for further research into the question which patients derive benefit from trastuzumab treatment35. The gene discussed is ERBB2; the disease is gastric adenocarcinoma.