6: Cancer genetics

Question 1

What causes cancer

Answer 1

Cells that divide and proliferate uncontrollably due to alterations / mutations in DNA

Question 2

Cancer mutations are to do either:

Answer 2

tumour suppressor genes being silenced
oncogenes being over-expressed

Question 3

Process of proliferation

Answer 3

Self synthesis of growth factors
Signal nearby cells to produce growth factors
Increase responsivity to growth factors

Question 4

immune evasion

Answer 4

normal ; recognition of cancer cells by immune system
some tumour cells contain PD-L1 (protein) which enables cancer to evade immune system by down-regulating T cells

Question 5

Benign cancers

Answer 5

Grow more slowly
well-differentiated
capsulated
Doesn’t invade neighbouring tissue
Does not metastasize

Question 6

Malignant cancers

Answer 6

Grow faster
poorly differentiated
Not capsulated
Invades neighbouring tissue
Invades basement membrane and metastasizes

Question 7

Benign cancer of epithelial tissue

Answer 7

Papilloma (lining epithelial)
Adenoma (gland)

Question 8

Malignant cancer of epithelial tissue

Answer 8

Squamous cell carcinoma
Adenocarcinoma

Question 9

Benign cancer of Mesenchyme tissue

Answer 9

Osteoma (bone)
Chondroma (chondrocytes)
Angioma (blood vessels)

Question 10

Malignant cancer of Mesenchyme tissue

Answer 10

Osteosarcoma
Chondrosarcoma
Angiosarcoma

Question 11

Benign cancer of lymph nodes

Answer 11

Lymphoma

Question 12

Benign cancer of blood cells

Answer 12

Leukaemia

Question 13

Inheritance of cancer mutations

Answer 13

Somatic mutations cannot be passed onto offspring (mature cells)
Germline mutations can be passed onto offspring

Question 14

Forms of cancer mutations

Answer 14

deletions
duplication
inversion
translocation
single base substitution (point mutation- silent, nonsense, missense)
chromosome instability
aneuploidy

Question 15

Passenger mutations

Answer 15

occur during cancer growth

Question 16

Driver mutations

Answer 16

Contribute to cancer growth

Question 17

Oncogene issues result in

Answer 17

increase in some kind of protein activity (enzyme) or loss of regulation

Question 18

A single mutation in an oncogene

Answer 18

can be sufficient for cancer development

Question 19

RAS controls

Answer 19

a lot of cellular signalling pathways as a switch
changes in RAS expression influence cancer development

Question 20

Two Hit Hypothesis

Answer 20

form of genetic damage not sufficient to enable cancer to develop - second hit initiates cancer e.g UV light exposure required to initiate melanoma development