Which process involves the growth of new blood vessels from existing ones?

The process that involves the growth of new blood vessels from existing ones is angiogenesis. This biological process is crucial for normal development and healing, as well as for the pathophysiology of various diseases, including cancer. In a tumor's microenvironment, angiogenesis allows tumors to receive the necessary oxygen and nutrients to grow, while also providing a pathway for cancer cells to enter the bloodstream and metastasize to other areas of the body.

Angiogenesis is regulated by various growth factors, such as vascular endothelial growth factor (VEGF), which stimulate endothelial cells to proliferate and form new capillaries. Enhanced angiogenesis is often a hallmark of tumors, making it a key target for cancer therapies aimed at inhibiting this process to starve tumors and prevent their growth.