Carcinogenesis

Question 1

what is the multi step model of carcinogenesis

Answer 1

the accumulation of genetic or epigenetic alterations that are colnally inherited and can convert a normal cell to a malignant one

Question 2

what are genetic alterations

Answer 2

mutations, deletions, amplifications or translocation of genes

Question 3

what are epigenetic alterations

Answer 3

chemical modifications to the DNA or chromatin e.g. methylation or acetylation

Question 4

what are tumour suppressor genes

Answer 4

they control the cell cycle and signal cell senescence / apoptosis
they can be methylated

Question 5

what are oncogenes

Answer 5

stimulate cell proliferation and promote cell survival and overcome cell senescence
activating mutations are tumourogenic

Question 6

what is cell senescence and triggers for this

Answer 6

irreversible arrest of proliferation

telomere shortening and oncogenic stress

Question 7

what is sunburn

Answer 7

acute UVB damage

cells cannot repair themselves and die

Question 8

types of photodamage

Answer 8

acute and chronic

Question 9

cause of chronic sun damage and features

Answer 9

UVA damage - penetrates more deeply
wrinkling - solar elastosis
aged skin

Question 10

cause of freckles

Answer 10

manifestation of sun damage in someone who cannot protect their skin adequately by tanning

Question 11

UV A/B is the principle carcinogen

Answer 11

UVB

Question 12

how does UVA cause damage

Answer 12

through oxidative damage

indirect DNA damage

Question 13

how does UVB cause damage

Answer 13

direct DNA damage

Question 14

exposure to chronic UV light causes keratinocytes to secrete?

Answer 14

immunosuppressive cytokines

Question 15

Langerhans cells lose their ability to antigen present in chronic UV exposure, true or false

Answer 15

true

Question 16

skin cancer is an imbalance between __ and __

Answer 16

proliferation and apoptosis

Question 17

BCC are genetically homogenous/heterogenous

Answer 17

homogenous

Question 18

SCC are genetically stable/unstable

Answer 18

unstable

Question 19

what mutation is common in non-melanoma skin cancer

Answer 19

p53 mutations are common and early

Question 20

what are AKs a sign of

Answer 20

indicative of photodamage

Question 21

list immunosuppressive drugs as direct carcinogens

Answer 21

ciclosporin
azathioprine
rapamycin

Question 22

how does imiquimod work

Answer 22

boosts the immune system and make the skin less immunosuppressed

Question 23

can only treat small areas of skin at a time with imiquimod, true or false

Answer 23

true

too much can cause rejection of organ

Question 24

HPV E6 inhibits apoptosis, true or false

Answer 24

true

Question 25

melanocytes are very resistant to UV induced apoptosis, true or false

Answer 25

true

therefore not radiosensitive

Question 26

freckles are a damage response, true or false

Answer 26

true

Question 27

chronic UV exposure is immunosuppressive, true or false

Answer 27

true

Question 28

UVR is both mutagenic and immunosuppressive?

Answer 28

yes

Question 29

what gene mutation is implicated in BCCs

Answer 29

PTCH gene and Hedgehog-patched signalling

Question 30

features of ‘transplant hands’

Answer 30

AK

viral warts

Question 31

azathioprine treatment photosensitises the skin to which type of UV?

Answer 31

UVA

Question 32

how does imiquimod / aldara work?

Answer 32

boosts immune system

Question 33

side effects of imiquimod and 5FU

Answer 33

inflammatory erythema

painful