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17 Cards in this Set
- Front
- Back
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What are the 4 major differences between oncogenes and tumor suppressor genes?
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Oncogenes: dominant, gain of function, somatic mutation, stimulates cell division
Tumor suppressor: recessive, loss of function, inherited/somatic, restrains cell division |
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What is an example of an oncogene and tumor suppressor gene?
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oncogene: protein kinase
tumor suppressor: transcription factor |
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What are the 4 types of mutations that was discussed that lead to cellular oncogene activation
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1. amplification
2. point mutations 3. chromosomal translocations 4. transposition to active chromatin domain |
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what are the 2 ways that oncogenes can be amplified?
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1. double minutes (small separate chromosomes)
2. insertions within normal chromosomes as homogeneously staining regions |
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what are the 2 ways to determine if an oncogene has been amplified?
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1. microarray
2. fish |
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Give an example of how a point mutation leads to oncogene activation
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- point mutation in RAS leads to a decrease in the rate of inactivation of cell division
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Give an example of how a chromosomal translocation leads to oncogene activation
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- CML has a 9,22 translocation where oncogene on chromosome 9 (abl gene) is put together with chromosome 22 (bcr) gene which generates a new protein
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Give an example of how a transposition to an active chromatin domain leads to oncogene activation
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- burkitt lymphoma
- oncogene, c-myc, from chromosome 8 is placed next to the IgH gene on chromosome 14, which is always active to transcribe B cells |
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discuss 2 hit hypothesis for tumor suppressor genes
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1. If one mutation is inherited, then only one other somatic mutation event is required to cause tumors
2. if gene is normal, 2 successive somatic mutational events is required to cause tumors |
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What events can lead a person to believe that a cancer patient had a germline mutational event plus a somatic mutation in a tumor suppressor gene?
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- multiple tumors
- bilateral - early onset |
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What is seen in a cancer patient that would lead someone to believe that they had a normal gene that was hit by 2 separate somatic mutational events?
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- single tumor
- unilateral - late onset |
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What are 5 ways that a person can lose heterozygosity if they were born with a germline mutation?
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- loss of who chromosome
- loss followed by duplication of mutated gene (ie RB) - mitotic recombination that causes both mutated alleles to be in one cell - deletion of wild-type allele - point mutation in wild type allele |
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are mismatch repair genes recessive or dominant?
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- recessive
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What 2 diseases were discussed that are caused by mutations in mismatch repair genes?
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1. Familial adenomatous polyposis
2. Hereditary nonpolyposis colon cancer |
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What is the relationship between microsatellite instability and mismatch repair genes?
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- microsatellite instability is when one area is duplicated many times
- mismatch repair genes are supposed to identify these regions and correct them |
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What are the 6 requirements for a successful tumor?
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1. independent external growth signals
2. insensitive to external anti-growth signals 3. avoid apoptosis 4. indefinite replication 5. sustained angiogenesis 6. tissue invasion and metastasis |
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What are the 3 important clinical relevance of studying genetics in cancer?
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1. more accurate diagnosis leads to better therapy
2. monitor remission/relapse 3. identify genes involved in tumorigenesis |
