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.
GBM arises from cells in the brain called glial cells. Neurons, which are generally post-mitotic, meaning they lose the ability to divide once they have achieved terminal differentiation. Glial cells, on the other hand, may continue to divide and replicate throughout life. There is evidence from in vivo and in vitro studies to suggest that some, if not all, astrocytomas arise in utero.
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, situated in the brain and spinal cord, have several important functions. Among these is providing support to the vascular cells that make up the blood brain barrier, providing nutrients to neuronal tissue and repairing damage caused by CNS trauma. Recent experiments indicate that one way that astrocytes communicate with nerve cells is by releasing glutamate, an excitatory neurotransmitter.
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.
GBM arises from cells in the brain called glial cells. Neurons, which are generally post-mitotic, meaning they lose the ability to divide once they have achieved terminal differentiation. Glial cells, on the other hand, may continue to divide and replicate throughout life. There is evidence from in vivo and in vitro studies to suggest that some, if not all, astrocytomas arise in utero.
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, situated in the brain and spinal cord, have several important functions. Among these is providing support to the vascular cells that make up the blood brain barrier, providing nutrients to neuronal tissue and repairing damage caused by CNS trauma. Recent experiments indicate that one way that astrocytes communicate with nerve cells is by releasing glutamate, an excitatory neurotransmitter.
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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