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Flashcards in MOD Deck (186)
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180

How does hiv raise cancer risk?

Lower immune system therefore increased risk of carcinogenic infection such as karposi's sarcoma

181

What is knudsons two hit hypothesis?

Both copies of a gene must be defective for a tumour suppressor gene to be deactivated. If one is defective due inherited mutation then you are much much more likely to experience the deactivation as only one further mutation is required.

182

How many copies of a gene need to be mutated to turn a protoncogene into an oncogene

One, it is upregulation.

183

What do protoncogenes commonly code for?

Growth factors (e.g. Pdgf)
Growth factor receptors (e.g. HER2)
Signal transducers (e.g. RAS activating cyclin D)
Cyclins
Transcription factors

184

Other than oncogenes and protooncogenes what other mutations can increase cancer risk?
Give examples

Dna repair genes
Xeroderma pigmentosum - mutation in nucleotide excision repair gene responsible for repairing UV damage
HNPCC - mutation in mismatch repair gene
Familial Ca breast - BRCA1/2 repair double stranded DNA breaks therefore mutation increases risk of translocation or gene loss.

185

What are the 6 hallmarks of cancer?

Self sufficient growth
Ignore stop growth signals
Ignore apoptosis signals
No limit to number of divisions
Ability to undergo angiogenesis
Ability to metastasise