EGF and gastric carcinoma: CD97, a member of the epidermal growth factor (EGF)–seven transmembrane subfamily, is overexpressed in most gastric carcinomas, where enhanced CD97 expression in gastric carcinoma is associated with tumor cell dedifferentiation and aggressiveness and directly correlates with clinical pathological parameters such as the tumor–node–metastasis (TNM) classification [3–5].