Effect of Radiotherapy on Expression of MUC1 and CK20 in Oral Mucosa

Objectives: A possible explanation for irradiation-induced damage of oral mucosa in the pathogenesis of osteoradionecrosis (ORN), through alterations of mucosal cell surface homeostasis and leading to breakage of oral mucosal barrier. The objective of this study is to determine the effect of RT to transmembrane Mucin 1 (MUC 1).
Methods: Oral mucosal biopsies were taken from irradiated patients (n=15) and controls (n=33). The presence of transmembrane MUC1 and anti-cytokeratin 20 (CK20) was examined by immunohistochemical methods. All the samples were prepared routinely for light microscopy examination. The localization, intensity and difference of the epithelial expression between control and irradiated specimens were analyzed. Statistical analysis was performed using IBM SPSS Statistic version 24 for Windows (SPSS, Chicago, USA).
Results: The presence of MUC 1 and CK 20 expression was strong in basal layer of epithelium cells in patients after radiotherapy compared to normal MUC 1 expression on the apical part of the superficial layer of epithelium in control samples. Irradiated samples had more MUC 1 expression than controls (p=0.005). Basal layers cells with strong expression of MUC 1 and CK 20 were identified as Merkel cells.
Conclusions: Abnormal expression of MUC 1 and the presence of Merkel cells in basal layer of the epithelium after radiation therapy may play a role in radiation therapy related problems such as ORN. More research on this subject is needed to explain the exact mechanism of irradiation damage to oral mucosa and ORN caused by irradiation therapy.