BCL-2 ONCOPROTEIN IN SURGICALLY RESECTED NONSMALL CELL LUNG-CANCER - POSSIBLY FAVORABLE PROGNOSTIC FACTOR IN ASSOCIATION WITH LOW INCIDENCEOF DISTANT METASTASIS

Background: The bcl-2 oncoprotein serves a regulatory function in perm itting several cell types to die in an apoptotic process. Its overexpr ession probably plays a role in tumorigenesis and tumor development. T he aim of this study was to determine the clinicopathological and prog nostic significance of the bcl-2 oncoprotein in patients with nonsmall cell lung cancer (NSCLC). Methods: Immunostaining for bcl-2 oncoprote in was performed on 182 operable NSCLCs. Results: Thirty-six patients (19.8%) showed a positive immunostaining for bcl-2 oncoprotein. Histol ogically, its incidence was higher in squamous cell carcinomas (29.6%) . Its expression status was inversely correlated with tumor developmen t-associated parameters such as tumor stage in NSCLCs, especially in s quamous cell carcinomas. bcl-2 positive patients with NSCLCs, especial ly squamous cell carcinomas, showed better overall survival and diseas e-free survival (DFS). In a multivariate analysis, this oncoprotein st atus had prognostic value in DFS for NSCLCs and in overall survival fo r squamous cell carcinomas. The recurrence of bcl-2 positive NSCLCs wa s significantly uncommon in distant extrathoracic organs. Conclusions: The expression of bcl-2 oncoprotein in NSCLCs may be an early event o f tumor development, especially in squamous cell carcinomas, and may b e of importance in determining tumor progression and prognosis. (C) 19 97 Wiley-Liss, Inc.