Photocarcinogenesis

Question 1

Bullous impetigo

blistering at site of infection

Answer 1

Caused by staphylococcus toxin A

Question 2

Staphylococcal scalded skin syndrome

Answer 2

Caused by staphylococcus toxin B
Most common in children
Low mortality rates

Question 3

Organism usually causing cellulitis

Answer 3

Beta haemolytic strep

Question 4

Another name for basal cell papilloma

Answer 4

Seborrhoeic wart

Question 5

Appear as firm, elevated pigmented nodules which may feel like a button in the skin
They are often found on the legs and commoner in females
There may be a history of trauma or insect bite

Answer 5

Dermatofibroma

Question 6

Keratoacanthoma

Answer 6

Rapidly growing epidermal tumours which develop central necrosis and ulceration
They occur on sun exposed sites and can grow to 2-3cm across
Whilst they may resolve spontaneously, best to surgicaly remove as they can mimic squamous cell carcinoma

Question 7

Where does Bowen’s disease most commonly develop?

Answer 7

Lower womens legs

Question 8

Where would you usually develop a pilar cyst?

Answer 8

The scalp

Question 9

Key characteristics or “hallmarks” of cancer

Answer 9

1. Insensitivity to growth signals
2. Insensitivity to anti-growth signals
3. Evade death (apoptosis)
4. Limitless potential to divide
5. Angiogenesis
6. Invasion and metastasis

Question 10

Basal cell carcinoma and exposure

Answer 10

Intermittent exposure

Question 11

Squamous cell carcinoma and exposure

Answer 11

Chronic exposure

Question 12

Melanoma and exposure

Answer 12

Intermittent exposure

Question 13

Lattitude and skin cancer

Answer 13

Incidence increases closer to equator

Question 14

Skin colour and eye colour and cancer

Answer 14

Red/fair haired individuals with blue eyes and freckling

Question 15

Where would patients with Xeroderma pigmentosum (XP) develop skin cancer?

Answer 15

Skin exposed areas

Question 16

UVC wavelength

Answer 16

200-280 nm

Question 17

UVB wavelength

Answer 17

280-315 nm

Question 18

UVA wavelength

Answer 18

315-400 nm

Question 19

Visible light spectrum

Answer 19

400-700 nm

Question 20

UV signature mutation

Answer 20

Cytosine to thymine (at dipyrimidine sites)

Question 21

NER

Answer 21

Nucleotide excision repair

Question 22

BER

Answer 22

Base excision repair

Question 23

DSB

Answer 23

Double strand break repair

Question 24

MMR

Answer 24

Mismatch repair

Question 25

Which UV is mainly responsible for initiating mutations?

Answer 25

UVB

Question 26

Which UVs are responsible for promoting mutations etc

Answer 26

UVB/UVA

Question 27

Estiamted action spectrum for cancer in humans?

Answer 27

298nm

Question 28

Age onset of MM?

Answer 28

<20 years

Question 29

Merkel cell skin cancer exposure

Answer 29

?cumulative

Question 30

HPV associated with which types of skin cancer?

Answer 30

BCC and SCC

Question 31

Metastases common in which type of cancers?

Answer 31

MM and MCC | malignant melanoma and merkel cell carcinoma

Question 32

Most common site for BCC?

Answer 32

Face and 1/3 sun protected sites

Question 33

Main site for SCC?

Answer 33

Sun exposed sited

Question 34

Main sites for malignant melanom?

Answer 34

Face, legs, back

Question 35

Main site for MCC?

Answer 35

Head/neck, sun exposed sited

Question 36

BCC formed from which type of cell?

Answer 36

Keratinocytes

Question 37

Major risk factor for BCC?

Answer 37

Immunosuppression (x10) | This is even BIGGER risk factor in SCC (65-250x)

Question 38

Eating this poison can increase risk of BCC?

Answer 38

Aresenic | -same for SCC

Question 39

Syndromes predisposing to BCC?

Answer 39

XP | Basal cell nevus syndrome (Gorlin syndrome)

Question 40

BCC risk factors

Answer 40

Intermittent sun exposure/sunburn Immunosuppression (10x) Ionizing radiation Arsenic ingestion ?photosensitising drugs Family/personal history of BCC/SCC

Question 41

SCC precursor lesions

Answer 41

Actinic keratoses | Bowen's disease

Question 42

Risk factors for SCC?

Answer 42

Chronic/cumulative sun exposure. Sunbeds. Immunosuppression (65-250x) Arsenic /petroleum products/organophosphates/smoking/scars/HPV ?photosensitising drugs Family/personal history of BCC/SCC

Question 43

SCC predisposing syndromes

Answer 43

``` XP Rothmund Thomson syndrome Bloom syndrome Werner syndrome Dystrophic epidermolysis bullosa Fanconi anaemia ```

Question 44

Precursor lesions for melanoma

Answer 44

Moles

Question 45

Where are melanomas usually found?

Answer 45

``` Chest/back (men) Legs (women) Palms and soles Growing under the nails Eyes ```

Question 46

Risk factors for melanoma

Answer 46

Risk factors: Intermittent sun exposure/sunburn. Sunbeds Ionizing radiation Immunosuppression ?photosensitising drugs/?heavy metals/?other occupational exposure Family/personal history of CM/BCC/SCC

Question 47

Melanoma predisposing syndromes

Answer 47

XP | Atypical mole syndrome

Question 48

Drugs associated with photocarcinogenesis

Answer 48

Psoralen Voriconazole Azathioprine Vemurafenib Photosensitising drugs Immunosuppressants Topical

Question 49

UV and langerhans cells

Answer 49

UV reduced number of langerhans cells

Question 50

UV and oxidative stress

Answer 50

Increases oxidative stress

Question 51

UV and exogenous compounds

Answer 51

UV interacts with exogenous compounds

Question 52

UV and IL10 and PGE2

Answer 52

UV upregulates inflammatory mediators including IL10 and PGE2