Hallmarks of Cancer
The fifth Hallmark of Cancer is the cell’s ability to induce angiogenesis. Angiogenesis is the development of new blood vessels. In other words, cancer cells are able to induce the creation of new blood vessels throughout the body. The blood that travels within these vessels transports oxygen and other vital nutrients to tissues that need them. The blood also takes away carbon dioxide and other metabolic wastes from these tissues. This transport system also works with tumors and helps the tumor to survive and grow.
The creation of new blood vessels also helps cancer cells spread to other tissues. Cancer cells travel through the vessels and proliferate at other parts of the body. This is called metastasis. For invasive cancers, angiogenesis begins rather early in the development of the tumor. Angiogenesis is induced by cancer cells sending out a signal to cells of the blood vessels and stimulating them to grow. This process is crucial for the tumor to grow and spread throughout the body.
An example of this Hallmark of Cancer can be seen with breast cancer. Breast cancer cells increase the prevalence of angiogenesis due to contributions from the environment including genetic changes and an increase in several different growth factors that support angiogenesis. Angiogenesis helps the cancer cells by providing additional routes for nutrients and for future metastasis. In order to prevent, or at least reduce angiogenesis, anti-angiogenic treatments have been studied. These treatments aim to reduce the cancer cell’s ability to produce angiogenic growth factors. Due to the cancer cell’s ability to acquire resistance to these treatments, methods to directly target cells of the blood vessels are also being researched. 1