Differential expression of hypoxia-inducible factor 1 alpha in non-small cell lung cancer and small cell lung cancer

Abstract

OBJECTIVES: The aim of this study was to compare the expression of hypoxia-inducible factor 1 alpha and vascular endothelial growth factor in small cell lung cancer and subtypes of non-small cell lung cancer and examine their relationships with clinicopathologic factors, response to treatment and survival. METHODS: We examined samples obtained by bronchial endoscopic biopsy from 55 patients with inoperable lung cancer (16 with adenocarcinoma, 17 with squamous cell carcinoma, and 22 with small cell lung cancer). Hypoxia-inducible factor 1 alpha and vascular endothelial growth factor were detected using immunohistochemistry. The diagnosis, treatment, and follow-up of patients were conducted according to the standard practice. RESULTS: A significant difference (p = 0.022) in hypoxia-inducible factor 1 alpha expression was observed between non-small cell lung cancer (75.8% positive) and small cell lung cancer (45.5% positive). The frequency of hypoxia-inducible factor 1 alpha nuclear expression was 88.2% in squamous cell carcinoma, 62.5% in adenocarcinoma, and 45.5% in small cell lung cancer. A significant correlation was observed between hypoxia-inducible factor 1 alpha and vascular endothelial growth factor expression (Fisher's exact test, p = 0.001) when all types of lung cancer were examined, either collectively or separately. CONCLUSIONS: The expression of hypoxia-inducible factor-1 alpha differs significantly between subtypes of lung cancer. These findings could help elucidate the biology of the different types of non-operable lung carcinomas and have implications for the design of new therapeutic approaches for lung cancer.