HIF-1α, or Hypoxia-Inducible Factor 1-alpha, is a protein that plays a crucial role in how cells respond to low oxygen levels, a condition known as hypoxia. It helps regulate various genes that are involved in processes like energy metabolism, blood vessel formation, and cell survival. When oxygen levels drop, HIF-1α becomes active and triggers these adaptive responses to help cells cope with the lack of oxygen. HIF-1α is important in many physiological and pathological conditions, including cancer, where tumors often grow in low-oxygen environments. By promoting the growth of new blood vessels, HIF-1α can support tumor survival and expansion. Understanding HIF-1α is essential for developing potential therapies targeting diseases related to oxygen deprivation.