Expression of HIF-1α and HIF-2α in non-small cell lung cancer

Objective To study the expression patterns and significance of hypoxia inducible factor (HIF)-1α and H1F-2α in non-small cell lung cancer (NSCLC). Methods The expression levels of HIF-1α and HIF-2α mRNA and protein were detected by quantiteve real-time reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting respectively when exposed to hypoxia (0.5% O2 )for various durations and the difference was compared. The expression of HIF-1α and HIF-2α protein in 140 surgically resected NSCLC samples was assessed by using immunohistochemistry, and its correlation with clinicopathology was explored. Results HIF-1α protein was transiently increased and reached a peak at 4 h and then decreased almost to at basal line 12 h later when the A549 cells were cultured under hypoxia,while HIF-2α protein was gradually up-regulated and persisted at a high level after a long-term hypoxia exposure. In 140 NSCLC samples,a significant correlation (P <0.05) was noticed between the expression of HIF-2α and the tumor size,lymph node metastasis and the TNM stage ( P <0.05). Tumor HIF-2α expression was also found as a statistically significant adverse prognostic factor in terms of the overall survival (P < 0. 05). Conclusion Taken together, it conclude that HIF-2α may play a dominant role in the process of tumor response to hypoxia, which suggests that it may be of more obvious value in therapeutic target research for NSCLC. Key words: Lung carcinoma;  HIF;  Immunohistochemistry