Angiogenesis is the process of formation new Blood Vessels from pre existing vessels. Angiogenesis is a normal process in growth and development of blood vessels as well as wound healing. If tissues need more oxygen then tissues release molecules that encourage blood vessel growth. Tumors also follow the similar procedure to improve their own blood supply in order to reassure their aberrant growth. VEGF protein is a major mediator of pathologic angiogenesis in firm tumors and ocular disease.

Sprouting Angiogenesis was the first recognized shape of angiogenesis. It takes place in some described phases. First, Biological signals known as angiogenic growth factors activate receptors present on endothelial cells present in pre-existing veins. Second, the activated endothelial cells begin to release enzymes called proteases that degrade the basement membrane in order to allow endothelial cells to escape from the original (parent) vessel walls. Intussusceptive angiogenesis is also known as splitting angiogenesis. Here the capillary wall extends into the lumen to split a single vessel in two.

Tumor Angiogenesis is the propagation of a system of blood vessels that seep in into Cancer growth, providing nutrients and oxygen and take away waste products. Tumor angiogenesis in reality starts with cancerous tumor cells discharge molecules that send signals to nearby usual host tissue. This signaling makes active certain genes in the host tissue that in turn make proteins to push enlargement of new blood vessels.