Hypoxia-inducible factor-1 expression predicts osteosarcoma patients' survival: a meta-analysis.

Osteosarcoma, the most common primary bone malignancy, is characterized by easily relapsing and metastasizing. Hypoxia-inducible factor-1 (HIF-1) plays an essential role in tumorigenesis, affecting tumor metabolism, differentiation, angiogenesis, proliferation and metastasis, and has been found to be associated with survival in patients with osteosarcoma. The possible prognostic value of HIF-1 was investigated in many studies, but the results were inconsistent. We therefore conducted a meta-analysis to elucidate the correlation of HIF-1 expression, analyzed by immunohistochemistry in osteosarcoma tissues, with prognosis. The association degree was assessed by calculation of the hazard ratio (HR) and risk ratio (RR) with corresponding 95% confidence intervals (CIs). Follow-up information was available for 486 patients from 7 studies. The results showed that high HIF-1 expression was associated with a worse prognosis when compared to low or undetectable HIF-1 expression, with an HR of 3.67 (95% CI 2.24-5.99; p<0.001) for overall survival (OS) and an RR of 3.72 (95% CI 2.26-6.13; p<0.001) for OS. The RR of 2.55 for disease-free survival (DFS) did not show any obvious relationship between a high level of HIF-1 and DFS (95% CI 0.95-6.87; p = 0.064). The stability of this result was tested by sensitivity analysis and no significant change was detected. This meta-analysis suggests that HIF-1 is an effective prognostic biomarker to predict OS in patients with osteosarcoma.