What are the roles of angiogenesis in cancer growth?

Angiogenesis is a significant factor in the progression of cancer. Angiogenesis is particularly important in cancer because cancers require the generation of new blood vessels to grow and spread. Specifically, for cancers to grow to be larger than one millimeter, angiogenesis needs to occur. To receive the blood they need, they send out chemical signals which trigger the process of angiogenesis. When this occurs, angiogenesis is harmful to the body, as it is forming new blood vessels which fuel the tumor with oxygen and nutrients. The tumor is then able to grow bigger in size, and cancer cells are able to metastasize elsewhere in the body.