The chapter discusses the regulation of neoplastic angiogenesis, which is crucial for the growth and metastasis of tumors. The balance between pro- and anti-angiogenic molecules in the tumor microenvironment determines the extent of angiogenesis. Interferon beta (IFN β) is often absent in tumors, leading to excessive angiogenesis. Therapies involving IFN α or β can inhibit angiogenesis and tumor growth. The process of cancer metastasis involves several steps, including tumor cell invasion, dissemination, and establishment in distant organs. The "seed and soil" hypothesis suggests that metastasis is influenced by both the tumor cells and the host environment. Angiogenesis is regulated by a complex network of pro- and anti-angiogenic factors, such as fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF), and interleukin 8 (IL-8). The microenvironment can directly influence the expression of these factors, affecting tumor growth and metastasis. Systemic administration of IFN α or β, or gene therapy with IFN β, has shown promise in inhibiting angiogenesis and tumor growth in various models. The antiangiogenic effects of IFNs are multifaceted, including inhibition of endothelial cell proliferation, migration, and invasion. Overall, the balance between pro- and anti-angiogenic factors in the tumor microenvironment is a critical factor in the regulation of neoplastic angiogenesis and metastasis.The chapter discusses the regulation of neoplastic angiogenesis, which is crucial for the growth and metastasis of tumors. The balance between pro- and anti-angiogenic molecules in the tumor microenvironment determines the extent of angiogenesis. Interferon beta (IFN β) is often absent in tumors, leading to excessive angiogenesis. Therapies involving IFN α or β can inhibit angiogenesis and tumor growth. The process of cancer metastasis involves several steps, including tumor cell invasion, dissemination, and establishment in distant organs. The "seed and soil" hypothesis suggests that metastasis is influenced by both the tumor cells and the host environment. Angiogenesis is regulated by a complex network of pro- and anti-angiogenic factors, such as fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF), and interleukin 8 (IL-8). The microenvironment can directly influence the expression of these factors, affecting tumor growth and metastasis. Systemic administration of IFN α or β, or gene therapy with IFN β, has shown promise in inhibiting angiogenesis and tumor growth in various models. The antiangiogenic effects of IFNs are multifaceted, including inhibition of endothelial cell proliferation, migration, and invasion. Overall, the balance between pro- and anti-angiogenic factors in the tumor microenvironment is a critical factor in the regulation of neoplastic angiogenesis and metastasis.