Skin cancer

Question 1

In what population is the incidence of malignant melanoma increasing?

Answer 1

White people

Question 2

Where is the incidence of malignant melanoma highest in the UK?

Answer 2

SW coast - most sun

Question 3

What is the trend in BCC incidence over the past 40 years?

Answer 3

Been increasing bc
Aging population
People go on holiday more
Sunbeds
Not wearing hats

Question 4

Define basal cell carcinoma

Answer 4

Malignant tumour arising from basal layer of epidermis

Question 5

Define squamous cell carcinoma

Answer 5

Malignant tumour of keratinocytes

Question 6

Define melanoma

Answer 6

Malignant tumour of melanocytes

Question 7

Define epidermodysplasia verruciformis

Answer 7

Rare autosomal recessive condition that predisposes to HPV induced warts and SCCs

Question 8

What role do UV light and p53 play in the pathogenesis of skin cancer?

Answer 8

UVB directly induces formation of photoproducts (mutations) in DNA:

• Cyclobutane pyrimidine dimers from 2 adjacent pyrimidines
• 6-4 pyrimidone photoproducts from pyrimidines

UVA:
Forms cyclobutane pyrimidine dimers (less effective than UVB)
Generates free radicals, can damage DNA and CM

Mutations that:
- Stimulate uncontrolled cell proliferation, e.g. abolishing control of normal cell cycle (p53)
- Alter responses to growth stimulating/repressing factors
- Inhibit apoptosis
Can cause cancer

Question 9

What role does human papilloma virus play in the pathogenesis of squamous cell carcinoma?

Answer 9

HPV is a cause of SCC, particularly in transplant situation