Intrinsic brain tumors, those that originate from neural cells within the brain and spinal cord, occur more frequently in older adults and children than they do in the general population. The main feature that makes intrinsic brain tumors different from cancers arising from other organs in the body is the fact that they rarely, if ever, metastasize outside the brain. Some cells in brain tumors do, however, stop dividing long enough to migrate a few millimeters away from the parent tumor to form new intracranial tumors. The most malignant of these is called glioblastoma multiforme (GBM).
Intracranial tumors are the most common cause of death by cancer in people under twenty years old. Second only to leukemia, they are the most common cause of cancer death in men aged 20-29. Neural tumors are the 5th leading cause of cancer fatalities in women aged 20-39.
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.
The human brain is home to three types of glial cells: oligodendrocytes, astrocytes and microglial cells. The most numerous of these are the astrocytes, star-shaped cells. These cells give rise to tumors called astrocytomas, the most malignant of which are the GBM. The median survival time in GBM is less than five months if left untreated.
Astrocytes are star-shaped glial cells found in the brain and spinal cord. The provide support to the endothelial cells that form the blood brain barrier, provide nutrients to nervous tissue and form a part of the repair process following trauma to the central nervous system. There is evidence to suggest that astrocytes communicate with nerve cells by releasing a neurotransmitter called glutamate.
Other glial cells include the oligodendrocytes. These have fewer 'arms' than do astrocytes. The primary function of the oligodendrocytes is to form the myelin sheath that insulates nerve cells and accelerates the rate of neural transmission. One oligodendrocyte can insulate up to 50 separate neuronal cells. The myelin sheath is subject to attack by the immune system in the chronic and debilitation condition, multiple sclerosis (MS).
Microglia are a special type of immune system cell resident within the central nervous system. These cells respond quickly to invasion from foreign bodies, embrace them through a process called phagocytosis and present them for destruction by T-cells. Resting microglia look very cute under the microscope, with tiny spines called processes. Activated microglia share more morphological characteristics with cells of the immune system, or leukocytes.
Intracranial tumors are the most common cause of death by cancer in people under twenty years old. Second only to leukemia, they are the most common cause of cancer death in men aged 20-29. Neural tumors are the 5th leading cause of cancer fatalities in women aged 20-39.
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.
The human brain is home to three types of glial cells: oligodendrocytes, astrocytes and microglial cells. The most numerous of these are the astrocytes, star-shaped cells. These cells give rise to tumors called astrocytomas, the most malignant of which are the GBM. The median survival time in GBM is less than five months if left untreated.
Astrocytes are star-shaped glial cells found in the brain and spinal cord. The provide support to the endothelial cells that form the blood brain barrier, provide nutrients to nervous tissue and form a part of the repair process following trauma to the central nervous system. There is evidence to suggest that astrocytes communicate with nerve cells by releasing a neurotransmitter called glutamate.
Other glial cells include the oligodendrocytes. These have fewer 'arms' than do astrocytes. The primary function of the oligodendrocytes is to form the myelin sheath that insulates nerve cells and accelerates the rate of neural transmission. One oligodendrocyte can insulate up to 50 separate neuronal cells. The myelin sheath is subject to attack by the immune system in the chronic and debilitation condition, multiple sclerosis (MS).
Microglia are a special type of immune system cell resident within the central nervous system. These cells respond quickly to invasion from foreign bodies, embrace them through a process called phagocytosis and present them for destruction by T-cells. Resting microglia look very cute under the microscope, with tiny spines called processes. Activated microglia share more morphological characteristics with cells of the immune system, or leukocytes.
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