Term
| Which genes inhibit and favour apoptosis? |
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Definition
bcl-2 and bcl-xl inhibit apoptosis
bwx, bnd, bcl-xs favour apoptosis. |
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Term
| Some B cell lymphomas overexpress bcl-2. This leads to.. |
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Definition
| Reduced cell death rather than increased proliferation. |
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Term
| DNA repair genes repair.. |
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Definition
| Non-lethal damage, preventing mutations in growth and apoptosis-regulating genes and spontaneous errors. |
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Term
| Are DNA repair genes themselves oncogenic? |
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Definition
| No - however, disability of DNA repair genes predisposes to mutations in oncogenes, tumour suppressor genes and apoptosis regulating genes. |
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Term
| Carcinogenesis is a multi-step process. This means... |
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Definition
Several events may be required to induce neoplasia.
Stepwise acquisition of different phenotypes occurs.
There are multiple genetic mutations - activation of several oncogenes and the loss of 2+ tumour supressor genes. |
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Term
| Are most human cancers due to environmental or genetic factors? |
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Definition
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Term
| What is the latent period? |
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Definition
| The period between application of known carcinogen and detection of tumour. |
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Term
| How are carcinogens identified? |
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Definition
| Epidemiological evidence, occupational risks, direct exposure, experimental observations. |
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Term
| What is the difference between direct carcinogens and procarcinogens? |
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Definition
Direct carcinogens are active in the form they are administered in.
Procarcinogens require metabolic conversion to ultimate carcinogens. |
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Term
| What two gene groups are there in DNA viruses? |
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Definition
Early genes, controlling early events such as replication of viral genome.
Late genes, controlling late events, such as syntehsis of viral proteins, viral assembly and virus production. |
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Term
| How do oncogenic viruses act on the cell? |
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Definition
1. Establish a stable relationship.
2. The life cycle is not completed.
3. Viral genome persists in transformed cell by integration / episodal form.
4. Have an active role in cellular transformation process - encode transforming proteins which bind to growth-regulating proteins. |
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Term
| What are RNA oncogenic viruses (retroviruses)? |
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Definition
| Single stranded RNA reverse transcribed by viral polymerase to DNA which then integrates into host genome. |
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Term
| Slow transforming retroviruses... |
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Definition
| Do not readily transform cells in vitro. Integrate DNA copy of viral genome close to significant host gene. |
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Term
| Fast transforming retroviruses... |
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Definition
| Are efficient at transformation. Carry v-onc (activated oncogene) into cell, integrating it into the host genome. |
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