What is Brain Cancer and How Does it Spread - Biology Essay


What is Brain Cancer and How Does it Spread - Biology Essay
Brain cancer is one of the most dangerous because nearly all tumors that arise in the brain are malignant. Although it is less likely that a primary tumor in the brain will metastasize and spread to other

parts of the body, the brain is such a sensitive and vital organ that surgery is usually very dangerous or impossible. Brain cancer is also harder to treat than other types of cancer because of the blood-brain barrier that doesn’t allow many types of drugs to pass into the brain. Because of this, new methods of treating this type of cancer are being developed such as the use of nanoparticles.

Brain cancer, like any other type of cancer, develops because of gene mutations. There are two main types of genes that if mutated can cause cancer. Proto-oncogenes and tumor suppressant genes are both involved in regulation of cell growth. Proto-oncogenes code for the proteins that are involved promoting cell growth and division. When a mutation occurs, these proto-oncogenes become oncogenes. Oncogenes cause too many of the growth stimulating factors to be produced, thus causing excessive cell growth and division. Tumor suppressant genes normally facilitate the sending of inhibitory and promoting messages to cells, but mutations can cause underproduction of the proteins that send inhibiting messages. As with oncogenes, this causes uncontrollable cell growth and division.

There are a many different classifications of primary brain tumors. They are first classified as glial or non-glial tumors. The glial tumors, which make up the majority of primary brain tumors, are called gliomas. The most frequently occurring type of glioma is an astrocytoma. Astrocytomas develop in the astrocytes and can arise anywhere in the brain. The most common place they occur is in the frontal lobe. After being identified an astrocytoma is given a grade of I through IV. A higher grade indicates faster growth. The worst of these is IV, or a Glioblastoma Multiforme (GBM).

Because of something called the blood brain barrier, tumors in the brain are much harder to treat. The blood-brain barrier is a membrane that controls various chemicals from being able to pass from the blood into the central nervous system. Unfortunately, this applies to many of the drugs that are used to treat cancer. This had made it necessary to develop new ways to treat tumors in the brain. One of these new developments is the use of nanoparicles in targeting and destroying cancer cells. These particles have the abilty to pass through the blood-brain barrier because they very small and often coated with a polymer of surfactant. These coatings make the particle more like other particles that are allowed to pass through the barrier. These tiny particles have been named PEBBLEs (Probes Encapsulated by Biologically Localized Embedding). These nanoparticles can be used to locate cancerous cells and then destroy them. When introduced into the blood stream the particles eventually enter the brain and because of the targeting agent in them they will all attach to the tumor. The MRI contrasting element that these particles also have attached to them allows the tumor to be seen because of the location of the particles. The amazing thing about these particles is that they are inactive until in the light. The chemical which makes this possible is called a photocatalyst. When whoever is treating the patient wants to activate the PEBBLEs an optic probe is inserted and reaction of the PEBBLEs destroys the surrounding cancerous cells. This technology is still in the clinical stages, but is very promising.

Brain cancer is one of the most dangerous forms of cancer and also one of the most difficult to treat. But with the amazing new technology that being developed its fair to say that this will not be the case for long.

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