Hypoxia-inducible factor-1α in non small cell lung cancer:: Relation to growth factor, protease and apoptosis pathways

Hypoxia-inducible factor (HIF)-1alpha is the regulatory subunit of HIF-1 that is stabilized under hypoxic conditions. Under different circumstances, HIF-1alpha may promote both tumorigenesis and apoptosis. There is conflicting data on the importance of HIF-1alpha as a prognostic factor. This study evaluated HIF-1alpha expression in 1172 consecutive patients with stage I-IIIA non small cell lung cancer (NSCLC) using standard immunohistochemical techniques. The extent of HIF-1alpha nuclear immunostaining was determined using light microscopy and the results were analyzed using the median (5%) as a low cut-point and 60% as a high positive cut-point. Using the low cut-point, positive associations were found with epidermal growth factor receptor (EGFR; p = 0.01), matrix metalloproteinase (MIMP)-9 (p = 0.003), membranous (p < 0.001) and perinuclear (p = 0.004) carbonic anhydrase (CA) IX, p53 (p = 0.008), T-stage (p = 0.042), tumor necrosis (TN; p < 0.001) and squamous histology (p < 0.001). No significant association was found with Bcl-2 or either Nor overall TMN stage or prognosis. When the high positive cut-point was used, HIF-1alpha was associated with a poor prognosis (p = 0.034). In conclusion, the associations with EGFR, MMP-9, p53 and CA IX suggest that these factors may either regulate or be regulated by HIF-1alpha. The association with TN and squamous-type histology, which is relatively more necrotic than other NSCLC types, reflects the role of hypoxia in the regulation of HIF-1alpha. The prognostic data may reflect a change in the behavior of HIF-lot in increasingly hypoxic environments. (C) 2004 Wiley-Liss, Inc.