[Expression of topoisomerase IIalpha in nasopharyngeal carcinoma and its clinical significance].

Background & Objective: TopoisomeraseIIalpha (TopoIIalpha) is a protein in eukaryotic cell with many different roles in DNA duplication and repair. It was reported that the expression level of TopoIIalpha was related to the prognosis of many malignant tumors. The aim of this study was to investigate the relationship of expression of TopoIIalpha in nasopharyngeal carcinoma (NPC) with clinicopathologic factors and its prognostic significance.

Methods: The expression of TopoIIalpha was observed in 114 NPC cases using immunohistochemical staining. All of the patients were divided into two groups according to the expression level of TopoIIalpha. Kaplan-Meier survival analysis was used to analyze the relationship of expression of TopoIIalpha with recurrence and metastasis of tumor after radiotherapy. Cox proportional hazards model analysis was used to analyze the factors related to local recurrence of tumor.

Results: The expression of TopoIIalpha in NPC cells ranged from 0 to 90%; the average percentage was (22.63+/-21.92)%. The positive rate of TopoIIalpha was 43.9% (50/114) when 20% was used as the cut-off point. The positive rate of TopoIIalpha was not related to the sex, age, pathological type, and clinical staging. The 3-year relapse-free survival rates of negative group and positive group were 93.1% and 74.3%, respectively (P=0.0027). The 3-year disease-free survival rates of the two groups were 77.9% and 58.9%, respectively (P=0.0091). The metastasis-free survival rates of the two groups were 81.1% and 77.6%, respectively (P=0.566). Cox proportional hazards model analysis showed that the local recurrence of tumor was independently affected by the expression of TopoIIalpha.

Conclusion: There is a high expression level of TopoIIalpha in a part of NPC.NPC patients with high expression of TopoIIalpha have a higher local recurrence rate and worse prognosis.