1 Genetics

Question 1

what percentage of cancers are sporadic?

Answer 1

95%

Question 2

The presence of male breast cancer in a family with other breast cancers, suggests which one of these genes may be mutated?

1) MLH1
2) MSH2
3) MSH6
4) BRCA1
5) BRCA2

Answer 2

5) BRCA2

Question 3

Which one of the following is not a tumour suppressor gene?

Answer 3

1) MSH2
2) MLH1
3) BRCA2
4) RET
5) APC

Question 4

which protein makes the RNA transcript?

Answer 4

RNA Polymerase

Question 5

what is the first amino acid in any protein?

Answer 5

Methionine (ATG)

Question 6

Mutations in BRCA1 and 2 can cause which 2 cancers?

Answer 6

ovarian and breast

Question 7

What 4 capabilities must be acquired for a cell to develop into a cancer?

Answer 7

Proliferative Signalling
Avoidance of apoptosis
Bypassing replicative senescence (stopping cells dividing unendingly)
Insensitivity to anti-growth signalling

Question 8

Function of Tumour suppressor genes

Answer 8

BREAKS

• Inhibit progression through cell cycle
• Promote apoptosis
• Act as stability genes

Question 9

Function of photo-oncogenes

Answer 9

PEDAL

• Stimulates the cell cycle
• Promotes cell division
• mutation = oncogene, with gain/ new type of function

Question 10

Difference in how mutations in photo-oncogenes vs TSG cause cancer

Answer 10

One mutated oncogene has tumour causing effect

Both copies of TSG must be mutated for cancer to form

Question 11

What are stability (caretaker) genes?

Answer 11

a type of TSG
act to minimise genetic alteration
account for commonest hereditary cancer predisposition syndromes (like hereditary breast cancer and colorectal cancer)

Question 12

Key differences between sporadic and familial cancer types

Answer 12

Sporadic:

• Common
• Late onset
• Single primary tumour

Familial:

• Uncommon
• Early onset
• Often multiple primaries
• More than one individual in same family affected by similar cancers or cancers at related sites

Question 13

Most of the more common cancer predisposition syndromes are inherits in which fashion? And due to an inheritance of an altered …

Answer 13

Autosomal dominant

due to inheritance of altered TSG

Question 14

What is the lifetime risk of developing a form of cancer?

Answer 14

50%

Question 15

What is your likelihood of developing breast cancer if you have the BRCA1 or 2 gene?

Answer 15

approx 80%

Question 16

other mutated genes which predispose to breast cancer

Answer 16

TP53
PALB2
PTEN

Question 17

Which gene is likely to be mutated if there is a family history of male breast cancer (and what is the likelihood of developing it in men with this gene mutation?)

Answer 17

BRCA2 and 5-6%