In gastric adenocarcinoma, HER2 gene amplification or protein overexpression is found in 7–34% of primary tumours (Takehana et al, 2002; Tanner et al, 2005; Park et al, 2006; Gravalos and Jimeno, 2008; Hofmann et al, 2008; Barros-Silva et al, 2009; Marx et al, 2009). The gene discussed is ERBB2; the disease is gastric adenocarcinoma.