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Flashcards in Ch. 25 Key Concepts Deck (11)
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most melanocytic nevi have activating mutations in which genes?

BRAF, or less often NRAS
- the vast majority never undergo malignant transformation


most of these are best regarded as markers of melanoma risk rather than premalignant lesions
- they are characterized by architectural and cytologic atypia and are associated with germline mutation in genes encoding cell cycle regulators (p16/INK4a, CDK4) and telomerase

dysplastic nevi


highly aggressive malignancy linked to sun exposure
- risk of spread is predicted by a number of tumor characteristics, particularly the vertical thickness of excised tumors

- often incites a host immune response and sometimes shows dramatic responses to antibody therapies that enhance T-cell immunity


what mutations are associated with melanoma?

- cell cycle regulators: p16/INK4a, CDK4
- pro-growth signaling factors: KIT, RAS, BRAF
- telomerase


the incidence of both basal cell and squamous cell carcinoma is strongly correlated with what?

increasing lifetime sun exposure


this type of carcinoma can progress from actinic keratoses but also arises from chemical exposure at thermal burn sites
- or in association with HPV infection in the setting of immunosuppression

cutaneous squamous cell carcinoma


this carcinoma has potential for metastasis but is much less aggressive than squamous cell carcinoma at mucosal sites

cutaneous squamous cell carcinoma


the most common malignancy worldwide
- is a locally aggressive tumor associated with mutations that activate Hedgehog signaling
- metastasis is very rare

basal cell carcinoma


classified based on the level of epidermal separation
- often caused by autoantibodies specific for epithelial or basement membrane proteins that lead to unmooring of keratinocytes

blistering disorders


associated with IgG autoantibodies to various intercellular desmogleins
- results in bullae that are either subcorneal or suprabasilar

- subcorneal = pemphigus foliaceus
- suprabasilar = pemphigus vulgaris


associated with IgA autoantibodies to fibrils that bind the epidermal basement membrane to the dermis
- also produce subepidermal blisters

dermatitis herpetiformis