Hypoxia, or low oxygen levels, within a tumor can trigger the "angiogenic switch," a key event in tumor progression. When tumor cells experience hypoxia, they increase the production of angiogenic factors like VEGF. This switch from a non-angiogenic to an angiogenic state is essential for the tumor to start forming new blood vessels. The angiogenic switch is regulated by various genetic and environmental factors, making it a complex yet crucial process in cancer development.
