Whereas in cancer, tumor-associated endothelial cells undergo abnormal angiogenesis through hypoxia-induced signaling via HIF-1α (Hypoxia-Inducible Factor-1 alpha) and VEGF secretion, hence, leading to leaky, dysfunctional, and hypoxic blood vessels, that foster tumor growth and metastasis, while impairing drug delivery and limiting its efficacy (36, 37). The gene discussed is HIF1A; the disease is neoplasm.