Skin tumour and cancer Flashcards
most common skin cancer?
BCC
how metastatic is BCC
not very
where does SCC appear
sun damaged skin
what is bowens disease
erythmatous plaque - CIS
what is an actinic keratosis
precursor lesion indicating sun damage
what is keratoacanthoma
spontaneously resolving SCC
true false - 25% of SCC patients will get another
false - 50% will
where else may SCC be found
chronic ulceration
scars
wounds
why are melanocytes more likely to metastasise
they are mobile as they moved form neural crest
prognosis of melanoma is dependent on?
breslow thickness
ABCDE of melanoma?
asymmetry irregular border colour diameter >0.7mm evolves quickly
how does xeroderma pigmentosum predispose melanoma
defective NER so increased likelihood
how does albinism increase likelihood of skin cancer
congenital absence of melanin so increased chance of DNA damage
how does immunosuppression increase likelihood of skin cancer
less likely to destroy cancer cells - thought to be
environmental carcinogens for skin cancer
coal tar, smoking
ionising radiation
chronic ulceration
previous skin cancer
how to prevent skin cancer
avoiding bad sunlight shade look after kids avoid sunbeds use darker/wear clothes sunscreens - at least SPF30 self-surveillance
weinbergs hallmarks of cancer?
evading immune response angiogenesis replicative immunity invasion evading tumour suppressors resisting cell death proliferative signalling genomic instability tumour promoting inflammation
true/false - if a cell has a p53 mutation it immediately becomes cancerous
false - many have mutant p53 in sun damage or older age but regulated by NER
UVB causes skin damage directly/indirectly
directly
describe how UVB causes skin damage
makes CPDs
and 6-4PPs causing a covalent CC-TT
how are CPDs and 6-4PPs removed
NER excises an DNA pol repairs
DNA sometimes causes further mutation
UVA causes direct/indirect skin damage
indirect
photoageing is produced by UVA/UVB
UVA
describe how UVA causes skin damage
forms 8-oxy-dG to cause C-A point mutation
repaired by BER