Expression Pattern of Apurinic/Apyrimidinic Endonuclease in Sinonasal Squamous Cell Carcinoma

Objective. To evaluate the apurinic/apyrimidinic endonuclease 1 (APE1)expression in sinonasal squamous cell carcinomas (SCC) and to examine the correlation between APE1 expression patterns and various clinicopathological factors associated with sinonasal SCC that include SCC with inverted papilloma (SCCwIP) and SCC alone. Study Design. Case-control study. Setting. Chungnam National University Hospital. Subjects and Methods. The expressions of APE1 were analyzed by means of immunohistochemistry in 30 sinonasal SCC, including 14 SCC patients associated with IP and 16 patients with SCC alone. A total of 19 patients who had been diagnosed with chronic rhinosinusitis with nasal polyposis and who required endoscopic sinus surgery were used as the control group. The degrees of APE1 expression were analyzed with respect to the following clinicopathologic variables: age, sex, T stage, histologic differentiation, distant metastasis, and recurrence. Results. Cytoplasmic staining of APE1 was significantly higher in SCC compared with SCCwIP (68.75% vs 14.29%). Cytoplasmic staining of APE1 was significantly associated with T stage (P=.044) in SCC and histologic grade (P=.0025) in sinonasal SCC. Nuclear staining of APE1 was significantly associated with distant metastasis (P=.022) in SCC. Conclusion. These results suggest that the nuclear and cytoplasmic expression of APE1 may be related to tumor invasiveness and prognosis in sinonasal SCC. The suppression of APE1 expression can potentially be a new target for future sinonasal SCC therapies.