High expression of hypoxia-inducible factor 1-alpha predicts poor prognosis in pancreatic ductal adenocarcinoma: a meta-analysis and database validation protocol

BACKGROUND: Hypoxia-inducible factor 1-alpha (HIF-1α) is overexpressed in pancreatic ductal adenocarcinomas (PDACs). However, the prognosis of high expression of HIF-1α in PDACs remains controversial because of lacking a solid support. A meta-analysis may help for a better understanding of the role of HIF-1α in the prognosis of PDACs. METHODS: By using a systematic approach, we conducted a meta-analysis from current literature. We performed an advanced search in PubMed, Embase, Cochrane Library and Web of Science databases. Recorded studies were published between September 1, 2001, and February 26, 2021, in English and related to the expression of HIF-1α in PDAC. We pooled and combined hazard ratios (HRs) and 95% confidence intervals (CIs) to show the effect of HIF-1α expression on overall survival (OS). We pooled also risk ratios (RRs) and 95% CIs to assess the correlation between HIF-1α expression and clinicopathological characteristics in PDAC. We evaluated publication bias among included studies through the Begg’s test and Egger’s test. From “Expression Plots” modules in the Gene Expression Profiling Interactive Analysis (GEPIA) database, we showed the difference of mRNA level for HIF1A between 179 pancreatic adenocarcinomas (PAADs) and 171 normal pancreatic tissues. RESULTS: This meta-analysis included 11 studies and 764 patients. High expression of HIF-1α was associated with shorter OS compared to low HIF-1α expression in PDAC (HR =1.74, 95% CI: 1.49–2.04, P<0.001). Patients with high expression of HIF-1α tended to have an increased risk of earlier lymph node metastasis (LNM) (RR =1.63, 95% CI: 1.36–1.95, P<0.001), and more advanced clinical stage (RR =1.64, 95% CI: 1.38–1.97, P<0.001) compared to those with low HIF-1α expression. Expression plots from GEPIA database showed HIF1A overexpressed in PDAC tissues compared to normal tissues (Log(2)FC =2, P<0.01). CONCLUSIONS: High HIF-1α expression associated with worse prognosis of PDACs compared to low HIF-1α expression. Since HIF-1α expression is greater in PDAC than normal pancreas, it could serve as a prognostic factor and potential therapeutic target. However, due to the complex role of HIF-1α in physiology and pathology, therapeutic intervention should be considered with caution.