Cancer as a Disease – Skin Cancer Flashcards Preview

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Flashcards in Cancer as a Disease – Skin Cancer Deck (38)
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1

What are the five layers of the epidermis?

Stratum corneum
Stracum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale

2

What are the main cell types in the epidermis?

Keratinocytes
Melanocyts
Langerhans Cells
Merkel Cells

3

State the types of skin cancer that come under each of the following types:
a. Keratinocyte derived
b. Melanocyte derived
c. Vasculature derived
d. Lymphocyte derived

a. Keratinocyte derived
Basal Cell Carcinoma
Squamous Cell Carcinoma
b. Melanocyte derived
Malignant Melanoma
c. Vasculature derived
Kaposi Sarcoma – endothelium of lymphatics
Angiosarcoma – endothelium of blood vessels
d. Lymphocyte derived
Mycosis fungoides

4

State two examples of genetic syndromes that massively increase the risk of getting skin cancer.

Gorlin’s Syndrome – regular BCCs
Xeroderma Pigmentosum – increased risk of BCC, SCC and malignant melanoma

5

Give two examples of viruses that can lead to skin cancer?

HHV8
HIV

6

What is the difference between the depth reached by UVB radiation and UVA radiation?

UVB – reaches sea level
UVA – reaches dead sea leve

7

How does UVB cause mutations in DNA?

Induces the formation of photoproducts
Particularly affects pyrimidines – causing cross-linking
Formation of cyclobutane pyrimidine dimers and 6-4 pyrimidine pyrimidone photoproducts

8

How are these mutations usually corrected?

Nucleotide excision repair

9

How can UVA promote skin carcinogenesis?

Forms cyclobutane pyrimidine dimers (but less effectively than UVB)
Also generates free radicals that can damage DNA

10

Name a condition that is caused by a defect in nucleotide excision repair.

Xeroderma pigementosum

11

What are the features of this condition?

Increased risk of BCCs, SCCs and melanoma
Photosensitivity and dry skin

12

What happens to keratinocytes in sunburn?

The UV damage leads to keratinocyte apoptosis
The apoptotic cells in UV overexposed skin are called sun burn cells

13

Describe the immunomodulatory effects of UV light.

UVA and UVB affect the expression of genes involved in skin immunity
It depletes Langerhans cells in the epidermis
This reduces skin immunocompetence and immunosurveillance

14

What are the consequences of UV therapy for psoriasis?

Increased risk of skin cancer UV can act on keratinocytes and cause DNA damage
If the Langerhans cells have been depleted then they will be unable to knock out the damaged cells so they could persist and become cancerous

15

Which system is used to categorise people based on their skin type and sensitivity to UV?

Fitzpatrick Phenotypes

16

Where are melanocytes found within the epidermis?

In the basal layer

17

What happens to melanin once it is produced by the melanocytes?

It is packaged into melanosomes and it passes along the processes of the melanocytes and is taken up by the keratinocytes
The keratinocytes put the melanosomes around their nuclei, which protects the nuclei from DNA damage

18

What are the two types of melanin?

Eumelanin – black/brown
Phaeomelanin – yellowish or reddish-brown

19

What is melanin formed from?

Tyrosine

20

What gene regulates the relative amounts of melanin produced?

MC1R

21

What is Lentigo Maligna?

Proliferation of malignant melanocytes within the epidermis
There is no risk of metastasis
This is also called melanoma in situ

22

What is it the name given to a large area of lentigo maligna that has a smaller area within it that has become invasive?

Lentigo maligna melanoma

23

What is a superficial spreading malignant melanoma?

Lateral proliferation of malignant melanocytes
They invade the basement membrane so there is a risk of metastasis

24

What is the ABCDE for the diagnosis of superficial spreading malignant melanoma?

Asymmetry
Border irregularity
Colour variation
Diameter (>0.7 mm and increasing)
Erythema

25

What is it called when a pale area appears in the middle of a melanoma?

Area of regression – this is associated with higher risk of metastasis

26

What is it called when you get a vertical proliferation of malignant melanocytes?

Nodular malignant melanoma

27

Describe the pattern of growth when a nodular melanoma arises from a superficial spreading malignant melanoma.

Downward proliferation of malignant melanocytes that is following previous horizontal growth

28

What is the type of melanoma that occurs on the palms and soles?

Acral lentiginous melanoma

29

What type of melanoma produced no melanin?

Amelanotic melanoma

30

What is the prognosis of melanoma based on?

Breslow thickness – thickness from the top of the tumour to the bottom