Could controlling blood vessel growth in the body be a key to treating rheumatoid arthritis, cancer and other diseases? The answer is perhaps, according to Mayo Clinic experts. Angiogenesis is the term used to describe blood vessel growth. Researchers are trying to understand and better control this complex process. Most recent research has focused on cancer. Tumours can’t grow to life-threatening size unless they’re adequately nourished by blood. Therefore, they produce substances called angiogenic factors that promote the growth of tiny blood vessels.