Epidermal Growth Factor Receptors in Cancer Tissues of Esophagus, Lung, Pancreas, Colorectum, Breast and Stomach

The levels of epidermal growth factor (EGF) receptors were investigated in surgically resected tumors of various origins including esophagus (n = 33), lung (n = 14), pancreas (n = 9), colorectum (n = 10), breast (n = 23) and stomach (n = 8). The (125)I‐EGF binding capacities of squamous cell carcinomas of esophagus and lung were exceptionally higher than those of the other cancer tissues. Immunohistochemical staining with an anti‐EGF receptor monoclonal antibody detected EGF receptors in the basal cells and parabasal cells of normal esophageal epithelium and in all the cancer cells of squamous cell carcinoma tissues of esophagus and lung. DNA replicating cells were examined by the bromodeoxyuridine staining method and it was found that the basal cells and parabasal cells of normal epithelium and peripheral cells of cancer pearls are proliferating. Contrary to this, a tumor antigen TA‐4, known as a specific marker for squamous carcinoma, was detected in the differentiated cancer cells and in middle‐layer squamous cells. These results strongly suggest that the increase in EGF receptor levels may be associated with the development of human squamous cell cancers of esophagus and lung. Thus, measurement of EGF receptor expression in tumor tissues has diagnostic value and should prove useful for the development of new therapies.