Illustration of the progression of angiogenesis. Angiogenesis is the physiological process of new blood vessel growth from PRE-EXISTING vessels. This is a different process from that of NEW blood vessel growth, which is called vasculogenesis. Angiogenesis is a fascinating process that is involved in both normal physiology (wound healing and formation of granulation tissue) and also in the pathological process of tumour transformation. Tumours require a rich blood supply in order to grow and continue rapidly dividing. To enable further growth angiogenesis is critical, and is therefore a key step in the transformation of a benign tumour into a malignant one. For this reason, inhibition of angiogenesis is a key target of anti-tumour cancer therapies. Illustration credit: Dr Jon Heras