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Anti-angiogenic therapy is a new type of targeted anti-cancer therapy. It involves the use of a new class of drugs that controls blood vessel growth to restore the health. The growing tumors need their own blood supply to enlarge and thrive. Blood vessels deliver oxygen and nutrients to the tumor, and cutting off the vasculature of the tumor literally starves the tumor of the vital supplies thus preventing its further growth and spreading.
The results can be more impressive when anti-angiogenic drugs are combined with other approaches to eliminate the tumors.
This type of therapy was first proposed in 1971, and it became a recognized method of cancer growth prevention in 1976. But the idea was very slow to develop, and only recently the drugs from this class have reached the hospitals. There are different types of anti-angiogenic therapy and the different drugs work in different ways to block the growth of blood vessels.
Why is Angiogenesis Important in Cancer?
Angiogenesis is a term that describes the formation of new blood vessels. It involves the growth, migration and differentiation of endothelial cell, the cells that form the lining of the internal walls of blood vessels. Specific chemical signals in the body control this process and the signals can either stimulate the new blood vessel formation and the repair of blood vessels that are damaged. Other chemical signal referred to as angiogenesis inhibitors interfere with the formation of blood vessels. Under normal circumstances, there is a balance between both of these signals so that blood vessels only start to form when they are needed.
For a tumor to get larger than a few millimeters, it must have its own blood supply. The chemical signals that stimulate blood vessel formation are responsible for the creation of tumor blood vessels. Tumors may also stimulate angiogenesis by giving off these chemical signals, thus stimulating the local blood vessels formation.
Both synthetic and natural angiogenesis inhibitors are being created in the laboratories around the world with the hope that these drugs will slow the growth of cancer, or completely prevent it from developing.
Types of Anti-Angiogenesis Treatment
There are three primary types of anti-angiogenesis treatment that can be considered for cancer patients. These include:
- Blocking blood vessel growth factor: Some drugs in this class work by blocking the vascular endothelial growth factor from being able to attach itself to the cell receptors lining the blood vessels. This prevents the blood vessel growth.
- Blocking signaling within the cells: The drugs in this class work by stopping the vascular endothelial growth factor receptors from transmitting the growth signals to the cells of blood vessels. These drugs are also called tyrosine kinase inhibitors or cancer growth blockers.
- Affecting the signaling between the cells: The drugs from this class work on the level of chemical signals that the cells rely on to stimulate the other cells to grow.