Tumor cells can proliferate under hypoxic conditions, which is closely related to the activation of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF). HIF-1α can enhance cell metabolism under hypoxic conditions and contribute to the activation of VEGF to induce tumor angiogenesis. HIF-1α expression may be a predictor of poor prognosis in GC, especially in Asia. This evidence concerns the gene HIF1A and gastric cancer.