Epidermal growth factor receptor expression on oral mucosa dysplastic epithelia and squamous cell carcinomas

The expression of the receptor for epidermal growth factor (EGF) has been determined on oral squamous cell carcinomas. Immunoreactive receptor was localized using a monoclonal anti-EGF-receptor antibody which reacts with sequences in the external domain of the receptor. Frozen sections were studied from 40 patients with squamous cell carcinomas. In 16 sections from the patients with the squamous cell carcinomas, normal differentiated oral mucosa was included and in 7 of these the patients had received preoperative radiotherapy. Sections from 6 other patients with squamous cell carcinoma contained dysplastic epithelia. EGF-receptor-positive cells were present in the basal cell layer on normal differentiated oral mucosa. In sections from patients receiving preoperative radiotherapy the EGF-receptor-positive cells were also found in the spinous cells. In dysplastic epithelia nearly all cells stained for the receptor. The distribution and staining intensity of the EGF receptor varied in the oral squamous cell carcinomas, 36 were positive. The staining pattern in the carcinomas obtained from patients receiving preoperative radiotherapy was not altered qualitatively. Nearly all poorly differentiated cells were stained, but when the tumor was moderately to well differentiated a reduction in the extent of staining in certain areas was seen, paralleling the findings observed in the differentiated upper layers of the normal oral mucosa. This was most pronounced for the epithelial pearls, where the EGF-receptor-positive cells were localized to the undifferentiated cells in the periphery. The results of the present investigation confirm the presence of the EGF receptor on undifferentiated cells, with the extent of the staining reaction on oral squamous cell carcinomas varying inversely with cellular differentiation.