Reduced expression of nuclear factor kB in oral mucosa undergoing preoperative chemoradiotherapy

Abstract

Radiotherapy as well as chemotherapy in head and neck cancer induces severe oral mucositis. Even after healing of the mucositis, however, the oral mucosa looking atrophic is known to be susceptible to injury and infection. In order to investigate such vulnerability of mucosa, we immunohistochemically studied the expressions of Ki-67, proliferating cell nuclear antigen (PCNA), cyclin D1, nuclear factor (NF)-kB, and keratinocyte growth factor (KGF) receptor in the oral mucosal keratinocytes undergoing preoperative concurrent chemoradiotherapy for oral cancer, compared with those of the oral mucosa without such therapy. As a result, the expressions of Ki-67, PCNA, and cyclin D1 were decreased in the chemoradiotherapy-treated oral keratinocytes. Interestingly, NF-kB expression, which is known to be enhanced in oral mucositis, was reduced after chemoradiotherapy. The chemoradiotherapy had no effect on the expression of KGF receptor in oral keratinocytes. In conclusion, the vulnerability of oral mucosa undergoing chemoradiation may be associated with reduced NF-kB expression and impaired growth activity.