1
Q

How long is the human genome?

A

➝ 3 billion BP

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2
Q

What % of the human genome codes for genes?

A

➝ 2%

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3
Q

What is DNA?

A

➝ A molecule which contains the human genetic code

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4
Q

What are genes?

A

➝The instructions to tell the body how to grow, develop and function
➝Consist of sections of DNA which the cell translates into proteins

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5
Q

How many genetic changes does one person have compared to another?

A

➝ 5 million different genetic changes

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6
Q

What is the lifetime risk for developing cancer?

A

➝ 1 in 2

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7
Q

What three types of cancer are there?

A

➝ Sporadic
➝ familial cancer
➝ high risk genes

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8
Q

How do sporadic cancers arise?

A

➝ due to acquired (somatic) mutations within a cell that occur during replications

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9
Q

What are the two internal changes that lead to sporadic cancers?

A

➝reactive oxygen species

➝ ineffective DNA repair mechanisms

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10
Q

What are the 4 external changes that lead to sporadic cancer?

A

➝UV light
➝ ionising radiation
➝ cigarette smoke
➝chemical consumption

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11
Q

What is inherited cancer risk?

A

➝ Genetic changes we are born with which increase the risk of developing cancer

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12
Q

What types of inherited cancer risks are there?

A

➝ High risk changes
➝ moderate risk changes
➝ low risk changes

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13
Q

If there is clustering of the same types of cancer in a family what is this called?

A

➝ multifactorial risk

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14
Q

If you have a lot of common variants what does this mean?

A

➝ risk of cancer is pushed up from the normal distribution

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15
Q

What are the high risk cancer predisposition genes for breast and ovarian cancer?

A

➝ BRCA

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16
Q

What are the high risk cancer predisposition genes for prostate and pancreatic cancer?

A

➝ BRCA2

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17
Q

What is the likelihood of having BRCA genes if you have breast or ovarian cancers?

A

➝ 5-10%

18
Q

What is the high risk cancer predisposition gene for colon cancer?

A

➝ Lynch

19
Q

What is multifactorial or polygenic risk?

A

➝ when you have multiple lower risk genetic variants

20
Q

How much genetic information do you share with your first degree relatives?

A

➝ 50%

21
Q

What are the 5 things you look at when assessing family history?

A

➝ Look at whether someone has had multiple cancers
➝Bilateral cancers e.g left kidney, right kidney
➝Look at the number of relatives that have had cancer
➝The types of cancer they have had
➝How close the family members are to each other

22
Q

What are the signs that breast cancer is likely to be genetic in a family?

A

➝If there are multiple individuals that develop premenopausal breast cancer there might be a genetic component
➝both ovarian and breast cancers in one family

23
Q

If you are older and develop breast cancer why is it less likely that it is genetic?

A

➝ the longer you live the more likely it is that cancer is sporadic

24
Q

What pathological subtypes of cancers increase the risk of having cancer predisposition genes and what genes are these?

A

➝ High grade serous ovarian cancer: BRCA1/2
➝Medullary thyroid cancer: RET
➝Triple negative breast cancer: BRCA1/2
➝Type 2 papillary kidney cancer: FH

25
Q

What is molecular testing and why is it done?

A

➝ Tumour testing

➝ it may identify genetic changes which could indicate inherited risk

26
Q

What test is done if someone has colon cancer and why?

A

➝ Immunohistochemistry to check for mismatch repair genes in Lynch Syndrome

27
Q

What sequencing is done if someone has breast cancer?

A

➝ BRCA sequencing

28
Q

What are two syndromic features of having a cancer predisposition gene?

A

➝ mucocutaneous pigmentation

➝ trichilemmoma

29
Q

What are the 4 decisions to make after assessment?

A

➝ Is there an increased inherited risk of cancer?
➝How high is the risk?
➝Does the patient need genetic testing to look for high risk cancer predisposition genes?
➝Does the patient and/or their relatives need extra screening or other measures to reduce cancer risk?

30
Q

How do you assess for inherited cancer risk?

A

➝ take 3 generational family history
➝ ages, types of cancer and number of affected relatives
➝ ethnic origin
➝ look for rare syndromic features
➝ use national genomic test directory eligibility to decide if genetic testing is indicated

31
Q

What is the chance of having a cancer predisposition gene if you have multifactorial/polygenic risk?

A

➝ <10% chance

32
Q

What is chemoprevention?

A

➝ taking medication to reduce cancer risk

33
Q

What are two examples of chemoprevention?

A

➝ breast cancer - taking tamoxifen or SERM

➝ colorectal cancer - taking aspirin

34
Q

What are two considerations when testing for high risk cancer predisposition genes?

A

➝ Implications for the individuals
Recurrence risks
Risks of other cancer

➝ Implications for relatives
How to share information
Concerns about children
Family planning options

35
Q

What is diagnostic testing for and who is it done on?

A

➝To confirm whether a cancer predisposition gene has caused the cancer
➝Done with a person with cancer

36
Q

What is predictive testing for?

A

➝To identify if an unaffected person carries a cancer predisposition gene
➝Insurance implications

37
Q

What are the three outcomes of testing?

A

➝ No genetic variant identified
➝No genetic variant identified
➝Disease causing variant in CPG identified

38
Q

What are the two things done after no genetic variant is identified in testing?

A

➝Screening and management on personal and family history

➝Referral for screening/further management only if indicated on above assessment

39
Q

What is done after a variant of uncertain significance is found in testing?

A

➝Referral for screening/further management only if indicated on above assessment
➝May be anxiety provoking for patients
➝Benign until proven guilty

40
Q

What is done after a disease causing variant in a cancer predisposition gene is found?

A

➝ Screening and management tailored to specific CPG

➝Should be reviewed by NHS clinical genetics service

41
Q

What are 4 differences between sporadic cancers and hereditary cancers?

A
Sporadic
➝ no increased risk of other cancers 
➝ usually small risk to relatives
➝ no genetic testing indicated 
➝ normal clinical management 

Hereditary
➝ high risk of recurrence/associated cancers
➝ high cancer risk in relatives
➝ testing and screening and preventative measures offered
➝ different treatment

42
Q

What kinds of mutations do sporadic and inherited cancers have?

A

➝ sporadic - somatic mutation

➝ hereditary - germline