HIF1A and cancer: Because HIF-1 regulates a wide variety of target genes required for angiogenesis, survival, metastasis, and glucose metabolism in cancer cells [21], it is important to explore whether existing anti-cancer agents could suppress tumor growth via HIF-1 inhibition, what approved drugs can be repurposed for anti-cancer drug development, and what upstream regulators will be most effective for modulating HIF-1 activity.