A Study of Apoptosis in Sinonasal Malignant Tumors : Bcl -2 and Fas-L Expression

Na, Han Jo; Do, Nam Yong; Lee, Do Yong; Choi, Ji Yoon; Hur, Jun; Park, Jun Hee; Lim, Sung Chul

Abstract

BACKGROUND AND OBJECTIVES: Apoptosis may play a key role in determining the growth, aggressiveness, and therapy responsiveness of tumors. Dysregulation of apoptosis can cause the tumorigenesis of sinonasal malignant tumors. The purpose of this study was to assess apoptosis and the expression of its related proteins, bcl-2 and Fas-L, in the sinonasal malgnant tumors.
MATERIALS AND METHODS
The study samples were obtained after surgical removal of 22 cases of inverted papilloma (IPs), 4 cases of IPs associated with squamous cell carcinoma (SCC), 14 cases of SCC in sinonasal cavity and 5 cases of normal inferior turbinate mucosa as a control. Apoptosis was evaluated by analysing DNA fragmentation using the TUNEL method. Bcl-2 and Fas-L expressions were assessed by immunohistochemical staining.
RESULTS
Apoptotic index (Al) was decreased progressively from IPs, through IP with SCC to reach the lowest level in SCC (p<0.05). Bcl-2/Fas-L expressions were increased as tumor progressed but Fas-L expression was statistically significant only (p<0.05). An inverse relationship between the Fas-L expression and apoptosis was observed as tumor progressed (p<0.05). No significant correlation was found between AI, expressions of bcl-2/Fas-L and other clinicopathologic factors.
CONCLUSIONS
These data suggest that bcl-2/Fas-L expressions are related to apoptosis and tumorigenesis of sinonasal malignant tumors. The inverse tendency between Fas-L expression and apoptosis might be an important role in evading surveillance of the immune system of sinonasal malignant tumors.