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17 Cards in this Set
- Front
- Back
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Define cancer |
Cancer is defined as the continuous uncontrolled growthof cells |
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Benign and malignant tumours |
Benign tumors stay confined to its original location • Malignant tumors are capable of invading surrounding tissue or invading the entire body |
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How are tumours classified? |
By cell type |
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Give an example of a cancer with- high case low mortality low case high mortality high case high mortality |
Prostate- high case but low morality Pancreatic- low case but almost everyone who has it dies Lung- high rate and most die |
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Common cells that cause tumours? what are these tumours called? % deaths caused by these? |
Epithelia cells -cover torgans -cause of prostate, lung, breast cancers etc -form basement membrane that provides scaffold to tissue, toumour cells can cause perferiations in the basement membrane causing cells to move away and therefore the cancer spreads -tumours called carcinomas -cause 80% of cancer-related deaths |
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How do cancer cells avoid immune destruction? |
Tumour cells can express protein PD-L1 which inactivates cytotoxic T-cells drug companies trying to inhibit PD-L1 so T-cells destroy cells |
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How do cancer cells display uncontrolled proliferation? |
- Cancer cells switch on growth promoting pathways. • They can also switch off growth suppressive pathways. • This imbalance can result in expansion of cancer cell population. |
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Examples of altered genetic make-up in cancer cells |
Tumour cells harbour extensive DNA alterations Tumour cell harbour all types of genetic alterations Point mutations Amplifications & deletions of chromosomal segments. Altered number of chromosomes |
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Define Aneuploidy |
altered number of chromosomes- should have a pair but could end up with 3 for example |
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Define chromothripsis |
Chromothripsis • Shattering and stitching together of large parts of chromosomes. • Observed in about 18% neuroblastoma |
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How do mutation rates differ across cancers? Why might there be a high mutation rates in animals and birds? |
Low substitution rates in paediatric cancer (0.1 basechange per megabase) • High substitution rates in lung cancer and melanoma(100 bases changed per megabase) • High mutation rates in mammals and birds could be due to high body temperature leading to spontaneous mutations! Mutation rate differ across different cancer types |
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Altered bioenergetics in cancer cells |
Since DNA sequence direct amino acid sequence, changes in cancer cell genome can change the protein copy number and also alter their function. This can have profound effect of cellular pathways. • Warburg effect- whether cell has O2 or not always does aerobic glycolysis. Aerobic glycolysis produces less ATP (4 mol ATP) but provides the fuel for glycolysis intermediates required for the biosynthesis of macromolecules and proliferation of cancer cells. -still called aerdobic glycolysis as it occurs even if o2 is present |
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Oncometabolite |
metabolite produced in cancer cell due to a mutation that changes metabolic pathways. eg mutation in isocitrate dehydrogenase converts isocitrate to 2-hydroxyl-glutarate (2HG) instead of a-ketoglutarate in the kreb cycle. 2HG goes on to inhibit several enzymes that require alpha ketoglutarate |
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Contact inhibition |
Normal cells stop growing when in contact with other cells cancer cells do not show this and keep growing |
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Angiogenesis -what is it? -Why does it happen? -how does it happen? -exploited for treatment? |
Formation of new blood vessels to allow nutrition to reachtumour. • A tumour without blood supply can only grow into a mass of 1 million cells ( 2mm). -Tumour produce angiogenesis stimulating factors. eg.Vascular endothelial growth factors (VEGF). • VEGF production is stimulated by low oxygen conditions“Hypoxia”. • VEGF targeting agents can block tumour angiogenesis and are being exploited for cancer treatment. |
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Common tissues for secondary tumours? |
Brain, bones and lungs |
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The invasion metastasis cascade |
-Primary tissue formation -cancer cells cause proliferations in basal membrane degrading it -attracted by signals eg epidermal growth factor -Enter blood vessel endothelial layer to entre blood stream |
