Since HIF-1α and Nrf2 are associated with the regulation of angiogenesis and tumor cell colony formation [31], we next tested whether As(III) affects capillary formation in endothelial cells and tumor colony growth of hepatoma cells in a HIF-1α or Nrf2-dependent manner using an in vitro matrigel assay and colony formation assay. The gene discussed is HIF1A; the disease is hepatocellular carcinoma.