2: Photocarcinogenesis

Question 1

What causes a cell to become cancerous?

Answer 1

Genetic mutations

Question 2

What is clonal evolution?

Answer 2

Accumulation of mutations over multiple generations of cells

Question 3

What are the hallmarks of cancer?

Answer 3

Uncontrolled cell division

Evade immune system

Invade tissues

Become immortal

Develop own blood supply

Don’t die

Question 4

What aspect of the immune system can melanoma cells use to prevent their own destruction?

Answer 4

Cytokines

Question 5

Which type of gene promotes cell division?

Answer 5

Oncogene

Question 6

What is an example of an oncogene?

Answer 6

RAS

RAF

Question 7

What is a proto-oncogene?

Answer 7

Unmutated oncogene i.e nothing is wrong with it yet

Question 8

Which type of gene suppresses cell division?

Answer 8

Tumour suppressor

Question 9

What is an example of a tumour suppressor gene?

Answer 9

Rb (retinoblastoma in cell cycle)

p53

Question 10

What do oncogenes trigger?

Through which signalling molecule do they achieve this?

Answer 10

Cell division and proliferation

Growth factors

Question 11

If a cell detects that its DNA is damaged, which tumour suppressor gene is activated?

Answer 11

p53

Question 12

Which tumour suppressor gene halts the cell cycle if it detects DNA damage?

What happens to cells if their DNA cannot be repaired?

Answer 12

p53

Apoptosis

Question 13

What are the two broad categories of skin cancer?

Answer 13

Malignant melanoma

Non-melanoma skin cancer

Question 14

What are two types of non-melanoma skin cancer?

Answer 14

Basal cell carcinoma

Squamous cell carcinoma

Question 15

In which epidermal layer are cancerous keratinocytes found in:

a) squamous cell carcinoma
b) basal cell carcinoma?

Answer 15

a) anywhere except the basal layer

b) basal layer only

Question 16

What are the risk factors for skin cancer?

Answer 16

UV exposure

Genetics

Age

Immunosuppression

Chemical exposure

Question 17

People with which category of skin are more likely to burn than tan?

Answer 17

I

Question 18

People with ___ skin are less likely to develop skin cancer.

Answer 18

dark

Question 19

Which pigment protects the DNA of basal cells from UV radiation?

Answer 19

Melanin

Question 20

Which genetic condition causes patients not to produce melanin, increasing their chances of developing skin cancer?

Answer 20

Albinism

Question 21

In which genetic condition does a patient’s DNA repair mechanism not work?

Answer 21

Xeroderma pigmentosum

Question 22

Name some chemicals which are thought to increase a patient’s risk of non-melanoma skin cancer.

Answer 22

Coal tar pitch

Soot

Arsenic

Question 23

Which two autoimmune GI conditions increase your chances of developing malignant melanoma?

Answer 23

Ulcerative colitis

Crohn’s disease

Question 24

What are some examples of immunosuppressant drugs which increase your chance of developing skin cancer?

Answer 24

Azathioprine

Cyclosporin

Monoclonal antibodies

Question 25

People who have received ___ \_\_\_ are more likely to develop skin cancer.

Answer 25

**Organ transplants** probs cuz they're on immunosuppressants

Question 26

Which wavelengths of light are responsible for skin cancer?

Answer 26

**UVA** **UVB**

Question 27

Which wavelength of light causes **direct** DNA damage?

Answer 27

**UVB**

Question 28

What wavelength of light causes **indirect** oxidative DNA damage?

Answer 28

**UVA**

Question 29

What kind of DNA damage does UVA exposure cause?

Answer 29

**Pyrimidine dimers** between bases

Question 30

Which wavelength causes pyrimidine dimers to be added to DNA? Which wavelength causes oxidation of DNA bases?

Answer 30

**UVB** **UVA**

Question 31

By which mechanism does DNA repair itself after **UVB** **radiation absorption**? How does this work?

Answer 31

**Nucleotide excision repair** 1. Damaged base is cleaved off 2. DNA polymerase fills in the gap using the other strand as a template 3. DNA ligase seals up the gaps

Question 32

Why does UV radiation cause immunosuppression?

Answer 32

**Langerhans cells are depleted** -- less antigen presentation to T cells **Regulatory T cells produced** **Anti-inflammatory cytokines produced**

Question 33

Mutations in which gene are associated with basal cell carcinoma?

Answer 33

**PTCH1**

Question 34

Which signalling pathway is involved in basal cell carcinoma?

Answer 34

**Hedgehog pathway**

Question 35

Which drug can be used to ?prevent basal cell carcinoma progression?

Answer 35

**Vismodegib**

Question 36

Which signalling pathway is involved in the development of melanoma?

Answer 36

**RAS / RAF pathway**

Question 37

Which type of drug can be used to block signalling pathways involved in the development of skin cancer?

Answer 37

**Monoclonal antibodies**

Question 38

The gene for which protein, involved in the cell cycle, can mutate to cause familial melanoma?

Answer 38

**CDK4**

Question 39

What should you do to cut your risk of developing skin cancer?

Answer 39

**Sunscreen** **Wear clothes** **Avoid sun between 11am and 3pm** **etc**