Expression of the epidermal growth factor receptor in esophageal cancer

The level of epidermal growth factor receptor (EGF-R) has been measured by a competitive binding assay in 45 human esophageal cancer tissues. The EGF-R level in the esophageal cancer tissue was found to be significantly higher than in specimens of gastric or colonic cancer. No correlation was observed, however between the EGF-R level and the pathological findings, such as the depth of the tumoral invasion, the degree of lymph node metastasis, and the histologic staging. Even so, the prognosis of the patients with a high level of EGF-R of more than 50 fmol/mg of protein was significantly worse than those with a low level of EGF-R and less than 50 fmol/mg of protein (p less than 0.01). Further, according to an immunohistochemical assay using anti EGF-R monoclonal antibody, EGF-R was focally stained in the basal cells and in the parabasal cells of normal esophageal mucossa, but was diffuse in almost all tumor cells of ane esophageal cancer. Thus, a good relationship with the quantitative level of EGF-R and its immunoreactivities was demonstrated, indications that EGF-R plays an important role in tumor progression and appears to be a useful prognostic factor in cases of esophageal cancer.