Blood vessels play a part in the transport of nutrients and oxygen to cells and tissues, while vascular endothelial cells themselves preserve the body’s homeostasis by secreting substances that contribute to tissue maintenance in the process of their differentiation and proliferation (blood vessel formation). Cancer cells are able to multiply because they generate blood vessels in cells that did not originally have blood vessels and therefore become able to take in nutrients. Vascular abnormalities are said to be closely connected to infectious diseases such as COVID-19, along with a variety of other diseases. Shedding light on blood vessel formation will undoubtedly become a new approach to treating disease.