Genetic predisposition to cancer Flashcards

1
Q

What do most cancers arise from

A

Genetic mutations either sporadic or inherited

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What kind of cancer mutation is non inheritable

A

somatic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What causes germ-line mutations

A

Hereditary -present in egg or sperm of parents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are tumours

A

clonal expansions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the three genetic processes associated with cancer syndromes

A

Oncogenes
Tumour suppressor genes
DNA damage-response genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are oncogenes

A

Mutated proto-oncogens that accelerate cell division

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How many mutations are needed to active oncogenes

A

1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the role tumour suppressor genes

A

Inhibit cell growth
promote apoptosis
Cells breaks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

When does cancer arrive with tumour suppressor genes

A

when both tumour suppressor genes fail

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where does the two hit in tumour suppressor genes occur resulting from carrier to cancer

A

first - germ line (carrier)

second - tumour formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What do DNA damage-response genes do

A

The repair mechanics for DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

When does cancer arrive from DNA damage-response genes

A

both genes fail, speeding the accumulation of mutations in other critical genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Give an example of a DNA damage response gene MMR

A

failure to mismatch due to single base mismatches or short insertions and deletions leads to accumulation of nucleotide repeats - Microsatellite instability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the evidence that DNA damage response genes aren’t working

A

Microsatellite instability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is de novo mutations

A

mutations occurring in there germ line of parents with no family history of hereditary cancer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How do we look for inherited cancers

A

family history

17
Q

What are most cancer susceptible genes

A

autosomal dominant with incomplete penetrance - therefore have genes but do not show the symptoms

18
Q

What is sporadic cancer

A

cancer by chance

19
Q

If tumours are heritable they are usually bilateral with increases the risk of what and why

A

secondary primer

because every cell carries the mutation

20
Q

How is Retinoblastoma cancer occur

A

due to heritable or non heritable tumour supressor genes

21
Q

What are the risks factors for breast cancer

A
Ageing 
Family history 
Hormones - late menopause/pill/HRT
Dietary factors 
Lack of exercise
22
Q

What is the most likely and second most likely gene to causes breast cancer and by what mutation

A

BRCA 1 then BRCA2

spordic

23
Q

What is BRCA1 genes functions

A
Checkpoint mediator

DNA damage signalling and repair

Chromatin remodelling (inactive Xchromosome)
24
Q

What is BRCA2s functions

A

DNA repair by HR (homologous recombination)

25
What else can BRCA1/2genes cause
Secondary breast cancer Ovarian cancer Male breast cancer
26
What cancer conditions can arise from tumour suppressor gene
Breast cancer ovarian cancer Retinoblastoma
27
What are the risk factors for colorectal cancer
``` Ageing Personal history of CRC or adenomas High-fat, low-fibre diet Inflammatory bowel disease Family history of CRC ```
28
How does Hereditary nonpolyposis colorectal cancer occur
DNA Mismatch Repair of HNPCC gene
29
what does polyposis and non polyposis mean
multiple adenomas present | No adenomas - but there is a risk of development
30
Lynch syndrome aka HNPCC is what
autosomal dominant genetic condition that has a high risk of colon cancer
31
What gene causes severe polyposis in colon cancer
FAP - familial adenomatous polyposis
32
What is clinical features of HNPCC
Tumor site throughout colon rather than descending colon | Extracolonic cancers: endometrium, ovary, stomach, urinary tract, small bowel, bile ducts, sebaceous skin tumors
33
Clinical Features of FAP
Estimated penetrance for adenomas >90% Risk of extracolonic tumors Untreated polyposis leads to 100% risk of cancer
34
What is autosomal recessive cancer syndrome and example
need to Inherit copies in both parents to show symptoms e.g. MYH polyposis
35
What explains a family with history of cancer but no identified mutation
Multiple modifier genes of lower genetic risk
36
How are cancer risk in Adenomatous Polyposis syndromes treated
Surveillance Surgery Chemoprevention