17- Clinical Cancer Genetics

Question 1

what factors contribute to most cancers?

Answer 1

most cancers result from a combination of genetic mutations, environmental influences, and lifestyle factors

Question 2

hereditary vs sporadic cancers

Answer 2

hereditary cancers:
- smaller percentage, rarer
- involve inherited germline gene mutations in every cell, contribute to an increased risk in developing a cancer in affected individuals

sporadic cancers:
- more common
- result from somatic mutations acquired during a person’s lifetime
- combination of chance mutations, environmental exposures, and aging, nothing inherited

Question 3

name the two types of mutations leading to cancer

Answer 3

constitutive/germline = inherited
somatic = acquired during a person’s life

Question 4

what is a constitutive/germline mutation? what is their clinical significance?

Answer 4

present in germline cells, inherited from a parent

contribute to hereditary cancer risk

clinical significance:
- inform future cancer risk
- guide treatment decisions
- provide information for other family members with shared genetic risk

Question 5

what are somatic mutations? what is their clinical significance?

Answer 5

occur in somatic cells, are acquired during a person’s life

contribute to the development of sporadic cancers

clinical significance:
- inform treatment decisions
- allow for targeted therapies
- providing reassurance to family members as they aren’t inherited

Question 11

LO: Understand the basic principles of inherited cancer susceptibility

Answer 11

inherited cancer susceptibility = the increased risk of developing cancer due to specific inherited genetic factors

key concepts:
1. genetic basis
- mainly driven by genetic mutations/alterations
- can be present in germline and affect someone’s risk of developing cancer

2. cancer predisposition genes/ TS genes
   - mutations can disrupt normal cell functions = increase risk of cancer
3. hereditary vs sporadic cancers
   hereditary cancers = result from inherited germline mutations
   sporadic cancers = from acquired mutations occurring during a person’s lifetime, not inherited
4. family history of certain cancers is a strong indicator of susceptibility, especially with multiple family members or with an early age of onset
5. syndromic features
   - some hereditary cancers are associated with specific clinical features or syndromic traits, recognising these can help early diagnosis and genetic testing
6. genetic testing, risk assessment, preventative measures