ERBB2 and gastric cancer: HER2 targeted therapies, including the fully humanized MoAb trastuzumab (Herceptin®; Roche) (Figure 1), pertuzumab (Perjeta®; Genentech, Roche, South San Francisco, CA, USA) (Figure 1) or the small-molecule tyrosine kinase inhibitors (TKIs), such as the dual EGFR/HER2 TKI lapatinib (Tyverb®; GlaxoSmithKline, Brentford, UK) and neratinib (Nerlynx®; Pierre Fabre, Paris, France), are approved in the treatment of breast and gastric cancers.