Abstract: Objective To study the pathogenesis mechanism of oral candida in patients with head and neck cancer undergoing radiotherapy from the perspective of virulence change.Methods In vitro phospholipase activity, hemolytic activity and adhesion to buccal epithelial cells of oral candida isolated from oral cavities of subjects with head and neck cancer undergoing radiotherapy were measured.Results Oral candida in the candida infection group and the candida colonization group after radiotherapy were detected.The phospholipase activity and adhesion ability to BEC showed no significant difference (P>0.05) in the candida infection,colonization group and the control group after radiotherapy. Secreted hemolysin in the candida infection group after radiotherapy was significantly higher than that of the other two groups (P<0.05) ; secreted hemolysin in the candida colonization group after radiotherapy and the control group showed no significant difference (P>0.05).Conclusions The change of hemolytic activity of oral candidia may be one of the pathogenic factors in head and neck cancer patients who had received radiotherapy.

Key words: head and neck cancer, radiotherapy, oral candidosis, virulence