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46 Cards in this Set

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  • Back
Brain tumors are diversified by (3)?
1. cell type
2. location
3. clinical presentation
T/F: most tumor symptoms are very specific (i.e. hemiparesis, visual changes)
False
_____ lobe seizures are the most common, followed by seizures in the ______ lobe.
Frontal; temporal
What can happen if the tumor happens on the dominant (left) side?
speech or language dysfunction
What percentage of tumors originate in the CNS? What percentage are secondary?
primary:40%
secondary:60%
What types of cancers most commonly metastasize to the brain?
Lung, Breast, Melanoma, GI cancers
Which type of tumor (primary or secondary) is usually more focal and discrete?
secondary
What kind of prognosis do metastatic tumors have?
poor, because the primary cancer is typically to advanced by the time it moves to the brain
How do cancer cells get around BBB?
BBB typically doesn't exist around tumors
What percentage of primary tumors are benign? malignant? uncertain?
75%
23%
2%
What is the most common primary brain tumor? second?
meningioma; astrocytic tumors
What is the most common malignant primary brain tumor?
glioblastomas (40%)
What percentage of pts with most malignant form of primary tumor survive 1 year?
less than 10%
Adults have more _____ tumors and children have a higher incidence of ______ or _______ type tumors.
1. astrocyctic
2. medulloblastoma
3. primitive neural ectodermal
Are the majority of astrocytomas malignant or benign?
malignant
What are the grades of astrocytomas and what do they indicate?
I/II: well differentiated, infiltrative but not malignant
III: anaplastic astrocytoma, considered malignant
IV: glioblastoma multiforme, considered malignant
With a low grade astrocytoma, pts have a relatively high likelihood of being alive __ to __ years after diagnosis.
10-15
What is the lowest grade infiltrative astrocytoma?
grade II
What are the characteristics of anaplastic astrocytoma?
-freq. highest in children and young adults
-median survival 36-48 mo
-can occur in brainstem
What are the histological features of anaplastic astrocytoma?
1.increases in number of 2.cells
3.pleomorphic cells
4.evidence of blood vessel formation
What is the most aggressive, difficult to treat primary brain tumor?
gliblastoma multiform (grade 4)
What are the histological features of glioblastoma (grade 4)?
-poorly differentiated
-necrosis
-tremendous vascular endothelial hyperplasia
-frequent mitosis
-rapid growth
Typical treatment for glioblastoma?
1st: surgical resection
2nd: irraditation
3rd: non-specific cytotoxic therapy
What phenotypic features of GBM make it difficult to treat and drive its morbidity and mortality?
1. Angiogenesis
2. Proliferation and survival
3. Invasion
What are the two ways in which a person can develop GBM?
1.GBM by de novo
2.transformation from lower grade to grade III then grade IV
What are the two molecular events that lead to de novo GBM?
1.amplification of EGFR receptor, an oncogenic amplification where the receptor is amplified or mutated so that it is on all the time
2. loss of tumor supressor gene LOH 10 called PTEN
What are the prognostic factors for malignant glioma?
histological grade, age of diagnosis, performance status, extent of resection, tumor location
3 conventional treatments for brain tumors?
surgery, radiation, chemotherapy
What are the antigens found in glia?
GFAP (glial fibrillary acidic protein) and MBP (myelin basic protein)
Gliomas develop from _______
glial-committed progenitor cells
Progenitor cells can become _______ within a ________
any kind of cell;
particular tissue
What is the ligand that drives the initial proliferation for the 8 cycles of glial progenitor cell division?
PDGF
What are the shared characteristics of gliomas and glial progenitor cells?
highly motile
robust proliferative potential
ofent assoc with bv and white matter tracts
typically have the same growth factor receptors
Most benign primary brain tumors are derived from ______ not _______
coverings of brain;
glial cells
What is pilocytic astrocytoma? What is the mutation?
low grade tumor typically found in kids; mutation in p53
T/F: Neurons can form tumors
F: tumors can only form from cells that proliferate
How do you make an unequivocal diagnosis of a brain tumor?
tissue biopsy
What is the typical way to grade a tumor?
# of possible tumor features (out of 4) plus one
What is the most common childhood tumor? What structures can it affect?
pilocytic astrocytoma; can affect optic nerve and cerebellum
Where do low grade astrocytomas often affect?
cerebral hemisphere
What mutation does anaplastic astrocytoma have?
p53 or p63 deletions
Which has better prognosis, oligodendroglial or astrocytic tumors?
oligo
Do meningiomas respond well to surgery?
yes (survival over 95%)
How do cancer cells kill neurons?
expose them to large amounts of glu (excitotoxic cell death)
What makes tumor cells so resistant to radiation?
production of glutathione (is a cellular anti-oxidant)
What does sulfasalazine do?
inhibits uptake of cys and production of glutathione by cancer cells --> leads to cell death and contains tumor growth