2: Photocarcinogenesis Flashcards Preview

Dermatology Week 3 2017/18 > 2: Photocarcinogenesis > Flashcards

Flashcards in 2: Photocarcinogenesis Deck (39)
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1
Q

What causes a cell to become cancerous?

A

Genetic mutations

2
Q

What is clonal evolution?

A

Accumulation of mutations over multiple generations of cells

3
Q

What are the hallmarks of cancer?

A

Uncontrolled cell division

Evade immune system

Invade tissues

Become immortal

Develop own blood supply

Don’t die

4
Q

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

A

Cytokines

5
Q

Which type of gene promotes cell division?

A

Oncogene

6
Q

What is an example of an oncogene?

A

RAS

RAF

7
Q

What is a proto-oncogene?

A

Unmutated oncogene i.e nothing is wrong with it yet

8
Q

Which type of gene suppresses cell division?

A

Tumour suppressor

9
Q

What is an example of a tumour suppressor gene?

A

Rb (retinoblastoma in cell cycle)

p53

10
Q

What do oncogenes trigger?

Through which signalling molecule do they achieve this?

A

Cell division and proliferation

Growth factors

11
Q

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

A

p53

12
Q

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

What happens to cells if their DNA cannot be repaired?

A

p53

Apoptosis

13
Q

What are the two broad categories of skin cancer?

A

Malignant melanoma

Non-melanoma skin cancer

14
Q

What are two types of non-melanoma skin cancer?

A

Basal cell carcinoma

Squamous cell carcinoma

15
Q

In which epidermal layer are cancerous keratinocytes found in:

a) squamous cell carcinoma
b) basal cell carcinoma?

A

a) anywhere except the basal layer

b) basal layer only

16
Q

What are the risk factors for skin cancer?

A

UV exposure

Genetics

Age

Immunosuppression

Chemical exposure

17
Q

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

A

I

18
Q

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

A

dark

19
Q

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

A

Melanin

20
Q

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

A

Albinism

21
Q

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

A

Xeroderma pigmentosum

22
Q

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

A

Coal tar pitch

Soot

Arsenic

23
Q

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

A

Ulcerative colitis

Crohn’s disease

24
Q

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

A

Azathioprine

Cyclosporin

Monoclonal antibodies

25
Q

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

A

Organ transplants

probs cuz they’re on immunosuppressants

26
Q

Which wavelengths of light are responsible for skin cancer?

A

UVA

UVB

27
Q

Which wavelength of light causes direct DNA damage?

A

UVB

28
Q

What wavelength of light causes indirect oxidative DNA damage?

A

UVA

29
Q

What kind of DNA damage does UVA exposure cause?

A

Pyrimidine dimers between bases

30
Q

Which wavelength causes pyrimidine dimers to be added to DNA?

Which wavelength causes oxidation of DNA bases?

A

UVB

UVA

31
Q

By which mechanism does DNA repair itself after UVB radiation absorption?

How does this work?

A

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
32
Q

Why does UV radiation cause immunosuppression?

A

Langerhans cells are depleted – less antigen presentation to T cells

Regulatory T cells produced

Anti-inflammatory cytokines produced

33
Q

Mutations in which gene are associated with basal cell carcinoma?

A

PTCH1

34
Q

Which signalling pathway is involved in basal cell carcinoma?

A

Hedgehog pathway

35
Q

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

A

Vismodegib

36
Q

Which signalling pathway is involved in the development of melanoma?

A

RAS / RAF pathway

37
Q

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

A

Monoclonal antibodies

38
Q

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

A

CDK4

39
Q

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

A

Sunscreen

Wear clothes

Avoid sun between 11am and 3pm

etc