genetic predisposition to cancer Flashcards
genetic processes associated with cancer
- the activation of oncogenes
- the deactivation of tumour suppressor genes
- the abnormal working of of DNA damage-response genes
proto-oncogene
normal gene that codes for proteins to rgeulate cell growth and differentiation
what changes a proto-oncogene into an oncogene?
mutation
how many ‘hits’ are required for oncogenes to cause cancer
only one mutation in the gene on one chromosome is required
how many ‘hits’ are required for tumour supressor genes to cause cancer?
2 mutations are required, one in each of the genes on each chromosome
what are DNA damage-response genes?
The repair mechanics for DNA
how many ‘hits’ are required to cause cancers due to DNA damage-response genes ?
two hits are required, one in each copy of the gene, this speeds the accumulation of other mutations in critical areas
what is miss match repair?
occurs when there is a base pair miss match, eg. T is paired with C in DNA replication. Repair mechanisms are used to fix this abnormality.
what happens if there is defective miss match repair mechanisms?
risk of cancer forming
what can microsatellite instability tell us?
that there is a problem with miss match repair
dysplastic tumour
A tumour that is benign but could progress to malignancy
example of oncogene
RET
example of tumour supressor gene
- BRCA1 and BRCA 2
- RB
what does a loss of function in BRCA 1 or BRCA2 cause?
breast cancer
what does a loss of function in RB gene cause?
retinoblastoma
