Antitumor effect of gefitinib ('Iressa') on esophageal squamous cell carcinoma cell lines in vitro and in vivo.

High expression of epidermal growth factor receptor (EGFR) is thought to be correlated with cell proliferation, invasion, metastasis, resistance to chemoradiotherapy, and poor prognosis in various kinds of human cancers. Blockade of EGFR signal transduction can be a promising strategy for cancer therapy. Approximately 40-70% of esophageal squamous cell carcinomas (ESCCs) show high expression of EGFR.