Week 2 - Inherited pre-disposition to cancer Flashcards
What is the percentage of cancers that are associated with a genetic pre-disposition?
4%
Name 3 key characteristics of cancers with inherited pre-disposition?
- Family history of (same) cancer
- Early age of onset, especially childhood
- Multiple cancers in one individual
- High occurrence of rare cancer
- Premalignant conditions, e.g. polyps
What is the definition of a Cancer Predisposition Gene?
Genes in which rare mutations confer >2x relative risk
of cancer, and at least 5% of individuals with relevant mutations
develop cancer
How many cancer pre-disposition genes are currently known?
114
What is the prevelance of Retinoblastoma?
1 in 20,000 children - 80 case/year
What is the average age of Retinoblastoma presentation?
90% present before 5 years of age.
What is the treatment(s) for retinoblastoma? (2)
Surgery & Radiotherapy
What are the two forms of Retinoblastoma and what percentage of cases do they represent?
Sporadic - 60%
Familial - 30%
What gene is mutated in Retinoblastoma and what type of gene is it?
RB1 - Tumour Suppressor Gene
What type of trait is pre-disposition inherited as?
Dominant
What is an obligate carrier?
A genetic carrier of a mutation but does not show any signs of the condition.
What is Li-Fraumeni Syndrome?
A very rare autosomal dominant genetic disorder that pre-disposes carriers to cancer development.
What is the diagnostic criteria for Li-Fraumeni Syndrome?
Diagnostic criteria:
- Individual <45 years with sarcoma
- 1st degree relative with any cancer <45 years
- Another 1st (or a 2nd) degree relative with any cancer <45yo or sarcoma at any age
What gene does Li-Fraumeni mutate to develop its cancer causing properties?
TP53
What does MEN2 stand for?
Multiple Endocrine Neoplasia (MEN2)
