Intrinsic brain tumors have two features that make them different from other types of cancer. One, is they rarely, if ever, metastasize to other organs in the body. Two, cells often break away from the main mass to invade the surrounding brain and form new growths a few millimeters or more away. These tumors are more common in children and the elderly than in the general population. The most malignant of these is called glioblastoma multiforme (GBM).
In men and women less than 20 years old, brain cancer is, after leukemia, the next most prevalent cause of cancer deaths. Apart from leukemia, intracranial-derived tumors are the next leading cause of fatality in men between the ages of 20 and 30. In females between 20 and 39 years old, brain tumors are the fifth most prevalent cause of cancer deaths.
GBM is rare, with only two or three new cases per 100,000 population. They account for one-fifth of all tumors inside the cranium. Because of GBM cells' ability to break away from the main tumor, migrate a few millimeters within the brain and start dividing again to form new tumors, they are impossible to completely eradicate by surgery. It's is like trying to remove all the butter from a slice of toast.
The type of cell that gives rise to GBM is the glial cell, of which there are three types. Nerve cells lose their ability to divide once they have reached terminal differentiation. Glial cells, on the other hand, are able to divide throughout the life of the individual. Evidence from both in vivo studies in the '60s and in vitro studies in the '90s and early 21st century support the hypothesis that most, if not all, intrinsic brain tumors begin forming in the developing fetus.
Glial cells come in three different forms: microglia, astrocytes and oligodendrocytes. Of these, astrocytes and astrocytic tumors, are the most common. The nastiest, most malignant and most deadly variant of astrocytoma is the GBM, which has a median time of survival without treatment of less than five months.
Astrocytes are characterized by their starry morphology and the presence of glial fibrillary acidic protein (GFAP). The normal function of astrocytes is to supply nutrients to nerve cells, support the vascular cells that comprise the blood brain barrier and repair damaged cells following trauma. New studies suggest that they communicate with neuronal cells by secreting glutamate, the brain's main excitatory neurotransmitter.
Oligodendrocytes are less spiny than their astrocytic cousins. Their main role in the nervous system is to provide a fatty sheath of insulation that makes more rapid nerve transmission possible. One oligodendrocyte can ensheath up to 50 neurons. The fatty sheath, called myelin, comes under attack from immune system cells in the debilitating condition known as multiple sclerosis (MS).
Microglia are the smallest members of the glial cell team. Their main function is to provide a rapid response to invading foreign bodies and prepare them for slaughter by T-cells. They do this by engulfing foreign matter in a process called phagocytosis. Resting microglia are the prettiest, and look like tiny astrocytes. Activated microglial cells look more bulbous with the processes less prominent.
In men and women less than 20 years old, brain cancer is, after leukemia, the next most prevalent cause of cancer deaths. Apart from leukemia, intracranial-derived tumors are the next leading cause of fatality in men between the ages of 20 and 30. In females between 20 and 39 years old, brain tumors are the fifth most prevalent cause of cancer deaths.
GBM is rare, with only two or three new cases per 100,000 population. They account for one-fifth of all tumors inside the cranium. Because of GBM cells' ability to break away from the main tumor, migrate a few millimeters within the brain and start dividing again to form new tumors, they are impossible to completely eradicate by surgery. It's is like trying to remove all the butter from a slice of toast.
The type of cell that gives rise to GBM is the glial cell, of which there are three types. Nerve cells lose their ability to divide once they have reached terminal differentiation. Glial cells, on the other hand, are able to divide throughout the life of the individual. Evidence from both in vivo studies in the '60s and in vitro studies in the '90s and early 21st century support the hypothesis that most, if not all, intrinsic brain tumors begin forming in the developing fetus.
Glial cells come in three different forms: microglia, astrocytes and oligodendrocytes. Of these, astrocytes and astrocytic tumors, are the most common. The nastiest, most malignant and most deadly variant of astrocytoma is the GBM, which has a median time of survival without treatment of less than five months.
Astrocytes are characterized by their starry morphology and the presence of glial fibrillary acidic protein (GFAP). The normal function of astrocytes is to supply nutrients to nerve cells, support the vascular cells that comprise the blood brain barrier and repair damaged cells following trauma. New studies suggest that they communicate with neuronal cells by secreting glutamate, the brain's main excitatory neurotransmitter.
Oligodendrocytes are less spiny than their astrocytic cousins. Their main role in the nervous system is to provide a fatty sheath of insulation that makes more rapid nerve transmission possible. One oligodendrocyte can ensheath up to 50 neurons. The fatty sheath, called myelin, comes under attack from immune system cells in the debilitating condition known as multiple sclerosis (MS).
Microglia are the smallest members of the glial cell team. Their main function is to provide a rapid response to invading foreign bodies and prepare them for slaughter by T-cells. They do this by engulfing foreign matter in a process called phagocytosis. Resting microglia are the prettiest, and look like tiny astrocytes. Activated microglial cells look more bulbous with the processes less prominent.
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