New Strategy of Treatment for Esophageal Squamous Cell Carcinoma Using Immunotoxin Which Reacts to Epidermal Growth Factor Receptor

Squamous cell carcinoma is by far the most common neoplasm of the esophagus and the survival rate of its patients is generally low [1]. To treat this cancer more effectively, it is necessary to develop a strategy of targeted cancer therapy. Most squamous carcinoma cells hyperproduce epidermal growth factor (EGF) receptor [2, 3], and EGF in turn promotes the growth of EGF receptor-hyperproducing squamous carcinoma cells in vivo [4]. Moreover, an elevated EGF receptor level is a significant prognostic factor for patients with esophageal squamous cell carcinoma [5]. Therefore, since EGF and its receptor system play an important role in the growth of this cancer, EGF receptor is an ideal cell surface object for targeted therapy. We synthesized an immunotoxin consisting of murine monoclonal antibody (B4G7) against human EGF receptor and gelonin, a 60s ribosome-inactivating protein. We studied the cytotoxic effects of the immunotoxin on squamous carcinoma cells and tumors, and investigated the possibility of it as a new treatment for squamous cell carcinoma.