Clinical Cancer Genetics Flashcards
(44 cards)
What is the inheritance pattern of the majority of high risk cancer predisposition genes?
Autosomal dominant
Is hereditary cancer more common or rarer than sporadic?
RARER - vast majority do not have an inherited cancer
Describe the difference of a constitutional (germline) mutation vs somatic
- Germline mutations are mutations that the person is born with due to a mutation being present in the gamete of a parent
- Somatic mutations are acquired and can not be given to children - can be thought of as ‘tumour only’ and they make up the vast majority of cancers
What is the difference between a hereditary and acquired mutation?
Hereditary = germline Acquired = any other time
What are the two different types of genetic susceptibility?
- High risk cancer genes
- Familial cancer
What are high risk cancer genes?
A single genetic change (mutation) in a high risk cancer gene and this increases their risk of cancer significantly
What are familial cancers?
Due to multiple lower risk genetic factors (so is multifactorial) to increase cancer risk - is much more common
Describe the frequency in the population of mutations causing a high risk of cancer in inherited disease
This is very low, most are low risk or intermediate risk (2-4 x chance) but few are high risk variants such as macular degeneration
What is an example of a high effect common variant influencing common disease?
Macular degeneration
What do the most common high risk cancer predisposition genes code for?
- Retinoblastoma
- Medullary thyroid
What can you use to identify genetically predisposed cancers?
Family history
Syndromic features
Tumour testing
Pathology of cancer
Describe the BRCA1 and BRCA2 genes in cancer risk
These are high risk breast cancer genes
What does a family history assessment show?
- Age of onset
- Type of cancer
How do you get a polygenic risk score?
GWAS for cancer associated SNPs
How can we sometimes use syndromic features to identify a patient that has a high risk cancer gene - name some
Some rare high risk cancer gene mutations show (mostly dermatological) syndromic features such as:
- trichilemmoma (PTEN gene mutation)
- mucocutaneous pigmentation (STK11 gene mutation)
How can you check if a mutation is germline?
blood test
What is stratified prevention?
Categorisation of the population into risk groups, each of which would be offered a different intervention
Explain what category B1 and B2 surveillance is
Guidelines for breast cancer, we take family history and look at family history and other things and use an algorithm to add up the risk
How often are all women screened for breast cancer?
3 yearly from 47-70
How big of a risk is B1 surveillance?
Medium
How big of a risk is B2 surveillance
High
If you are on B1 surveillance how often do you get invited for breast cancer screening?
- Anually 40-50
- 3 yearly 50-70
How often do you get invited for breast cancer screening if you’re on B2 surveillance?
- Annual 40-60
- 3 yearly 60-70
What is tamoxifen?
Anti-oestrogen drug, shown to decrease risk of developing cancer if they come from a family with increased susceptibility of cancer
