HIF1A and cancer: VEGF-A is likely the most important factor driving tumor angiogenesis.18 We have previously shown that HIF-1α upregulates the expression of VEGF-A in sarcomas,19 and circulating levels of VEGF-A are elevated on average tenfold in patients with sarcoma compared to controls.20 The expression of VEGF-A in sarcomas correlates with extent of disease and survival.21 Inhibition of VEGF-A or its receptors can effectively suppress tumor angiogenesis in mouse sarcoma models,19, 22 and numerous anti-VEGF agents are in various phases of clinical trials or approved for patients with cancer.23