Photocarcinogenesis Flashcards Preview

RB Y2 Dermatology > Photocarcinogenesis > Flashcards

Flashcards in Photocarcinogenesis Deck (23)
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1
Q

define clonal evolution

A

series of mutations that accumulate in several generations

cell eventually becomes mutated enough to be cancerous

2
Q

define oncogene

A

over active form of a gene that positively regulates cell division

doesnt require GF

3
Q

proto-oncogene

A

normal not yet mutated form of oncogene

4
Q

oncogene examples

A

Ras, Raf

5
Q

what is inactivated during tumour growth

A

tumour suppressor

6
Q

what type of skin cancer can sunbeds cause

A

ALL

7
Q

what type of skin cancer does chronic long term exposure cause

A

SCC

8
Q

what type of skin cancer does burning and intense intermittent exposure cause

A

melanoma and BCC

DOUBLE RISK

9
Q

what are 2 genetic predispositions to skin cancer

A

albinism and xeroderma pigmentosum

10
Q

xeroderma pigmentosum

A

ability to repair damage caused by UV light is impaired, patients have extreme photosensitivity

11
Q

what happens neurologically in xeroderma pigmentosum

A

neurological degeneration

12
Q

defect in what genes causes xeroderma pigmentosum

A

NER genes

13
Q

what autoimmune conditions inc risk of skin cancer

A

crohns (80%) and UC (23%)

14
Q

what effect does organ transplantation have on skin cancer risk

A

NMSC risk 29-33 times higher (especially SCC) malignant melanoma risk more than double

15
Q

UVB effect on DNA

A

DIRECT

the signature type of DNA damage is PYRIMIDINE DIMER

16
Q

what is the signature mutation of UVB

A

TT to CC

17
Q

name 2 types of UVB induced DNA lesion

A

cyclobutane pyrimidine dimer (CPD) and 6-4PP

18
Q

what bonding is present in CPD and 6-4PP

A

covalent

19
Q

how are CPD and 6-4PP removed

A

nucleotide excision repair

20
Q

UVA damage to DNA

A

indirect via oxidation of DNA bases espeically dG to 8-oxo-dG

21
Q

UVA signature mutation

A

C to A point mutation

22
Q

how are oxidised bases (UVA) repaired

A

base excision repair

23
Q

what type of skin cancer does UVA cause

A

non melanoma skin cancer