Familial Cancer Syndrome Flashcards
What is the function of landscaper cells?
Control surrounding stromal environment
The mutation of what will most likely cause cancer? Describe this genes function
- Gatekeeper genes
- Monitor/control cell division & death
- P53-prevents the accumulation of mutations
What is Knudson’s two hit hypothesis?
- Most cancer genes obey this
- 2 genes in a single cell required to be knocked out for the cell to become cancerous
- Cell can function with only 1 normal gene
What is the difference between sporadic change and inherited change of a gene?
- Sporadic start with 2 normal genes both must be inactivated to be cancerous
- Inherited start with 1 normal gene only this needs to be inactivated for cancer
What inheritance pattern do most cancer syndromes show?
Autosomal dominant
What types of mutations can lead to cancer syndromes?
- Splice site mutations
- Large deletions & duplications
- Translocation
What are clues that cancer is sporadic?
- Onset at older age
- One cancer in individual
- Unaffected family members
- Cancers that are rarely genetic (cervical/lung)
What are clues that a cancer is inherited?
- Onset at younger age
- Multiple primaries in individual
- Other family member s affected
- Same type/genetically-related cancers
Describe inherited Retinoblastoma
- Both genes mutated
- One mutation present in gremlin
- Inherited cases occur at younger average age
- Bilateral cases almost always gremlin
- Other cancer risks
- Early screening for children at risk
Describe familial adenomatous polyposis (FAP)
- Hundreds of bowel polyps from teen onwards
- High risk of bowel cancer if untreated
- Other features= demoed tumours, osteomas
- APC tumour suppressor gene
- Autosomal dominant
Describe hereditary non-polyposis colorectal cancer (NHPCC)
- Polyps common not polyposis
- 60-80% risk of bowel adenomas
- Other cancer risks= endometrial/ovarian
- Mismatch repair genes
- Autosomal dominant
What is the Amsterdam criteria for HNPCC?
- One member diagnosed with colorectal cancer before 50
- 2 affected generations
- 3 affected relatives one of them 1st degree relative
- FAP excluded
- Tumours verified by pathological examination
- All criteria above met
Describe Li-Fraumeni Syndrome
- P53 mutation
- Rare
- Autosomal dominant
- Breast, sarcoma, brain, leukaemia
- Avoid radiotherapy
- Poor prognosis
- 50% risk by 40 100% over lifetime
What is the function of the BRCA gene?
DNA repair
What genes are tumour suppressor genes?
- Gatekeeper
- Caretaker
- Mutation=loss of function
What is the function of caretaker genes?
Improve genomic stability
