In mouse-xenografted UM-SCC-22B squamous carcinoma tumours, GCN2 knockdown supresses VEGF levels and results in a reduction in both blood vessel density and tumour volume [20], indicating that in vivo, GCN2's response to AAD is key to angiogenesis initiation via VEGF, a response that would usually promote vascular health in a non-cancerous state, but here promotes tumorigenesis. This evidence concerns the gene EIF2AK4 and neoplasm.