IMMUNOHISTOCHEMICAL AND QUANTITATIVE CHANGES IN SALIVARY EGF, AMYLASEAND HAPTOCORRIN FOLLOWING RADIOTHERAPY FOR ORAL-CANCER

Epidermal growth factor (EGF), amylase and haptocorrin are molecules p roduced in the salivary glands. The aim of the present study was to de termine immunohistochemical and quantitative alterations in EGF as com pared with haptocorrin and amylase following radiotherapy for oral can cer. Changes in the salivary secretion of EGF are of interest because of the importance of EGF in mucosal regeneration. Immunohistochemical studies on normal tissue from parotid and submandibular glands have de monstrated EGF in the serous acini with a tendency to single cell expr ession in the parotid gland. Amylase has been found in the serous acin i of both the submandibular and parotid glands. Haptocorrin was locali zed in the duct system of both glands. In the submandibular glands wit h radiotherapy induced sialoadenitis only very few acini with weak or no staining for EGF and amylase were demonstrated, while no changes we re observed in the staining for haptocorrin. Analysis on stimulated wh ole saliva samples collected from 20 healthy individuals and from 20 p atients prior to, and 1, 2 and 3 weeks following radiotherapy showed s ignificant reduction in salivary contents of EGF and amylase after tre atment as expressed per g protein (p < 0.0002). The salivary content o f haptocorrin increased significantly after treatment (p < 0.002). The se alterations may be explained by the different cellular sites of the molecules studied, the serous acini being more sensitive to ionising radiation than the duct system. The concentration of EGF in saliva bef ore treatment was significantly higher in patients than in the control group (p < 0.02), which may indicate that the tumors induce increased secretion of salivary EGF, or alternatively that the oral tumors cont ribute with EGF to the saliva. In conclusion we have demonstrated a re duction in the mitogenic peptide EGF both immunohistochemically and qu antitatively following irradiation for oral cancer, results which may contribute to the understanding of the clinical signs of mucositis.