Skin Cancer Flashcards
(35 cards)
skin is made up of what 3 layers?
- epidermis
- dermis
- hypodermis
what are the 4 layers of epidermis?
- stratum cornea
- stratum lucidum
- stratum spinous
- stratum basale
What are the 4 major types of skin cancer?
- Keratinocyte derived
eg basal cell carcinoma, squamous cell carcinoma
aka Non melanoma skin cancer (NMSC) - Melanocyte derived
eg Malignant melanoma - Vasculature derived
eg Kaposi’s sarcoma, angiosarcoma - Lymphocyte derived
eg Mycosis fungoides
skin cancer arises due to accumulation of genetic _____ –> which causes it to ______ in a uncontrolled manner
skin cancer arises due to accumulation of genetic mutation –> which causes it to proliferate in an uncontrolled manner
What are some causes of skin cancer?
give examples of each cancer derived from each cause/.
- Genetic syndromes
Gorlin’s syndrome
xeroderma pigmentosum - Viral infections
HHV8 in Kaposi’s sarcoma
HPV in SCC - UV light (most common cause)
BCC, SCC, malignant melanoma - Immunosuppression
drugs, HIV, old age, - leukaemia
Malignant melanoma = tends to be of higher prevalence in white ethnicity individuals
-
Basal cell carcinoma = increasing in incidence
what are they caused by?
sun exposure
Genetics
UVA –>has higher penetration
- major cause of skin aging
contributes to skin carcinogenesis
-
How doe UVB induce DNA Abnormalities of the skin?
- UVB directly induces abnormalities in SNA
- -> induces photoproducts
- -> affects pyramiding Cytosine + thymine ases
–> usually repaired quickly by nucleotide excision repair
What things can UV damage induce to DNA?
- cell division
- dna repair
- cell cycle arrest defect.
What mutations can cause skin cancer?
- Mutations that stimulate uncontrolled cell proliferation
Eg abolishing control of the normal cell cycle (p53 gene)
2/ Mutations that alter responses to growth stimulating / repressing factors
3.Mutations that inhibit programmed cell death (apoptosis)
what is sub burn?
Exposure to UV –> build up of mutations –> apoptosis of the keratinocyte occurs –> protects cells from becoming cancer cells.
UVA and UVB effect the expression of genes involved in skin immunity
–> Depletes / increases Langerhans cells in the epidermis
UVA and UVB effect the expression of genes involved in skin immunity
–> Depletes / increases Langerhans cells in the epidermis
in exposure to UV, there will be a reduced immunocompetence + immunosurveillance
-
melanin is produced by
melanocytes within the basal layer of the epidermis
skin color depends on:
the amount and type of melanin produced
What are the 2 types of melanin formed?
Eumelanin – brown or black
Phaeomelanin – yellowish or reddish brown
—> Melanin is formed from tryosine via a series of enzymes
regulation of melanin type production is controlled by
MCR1 gene
define malignant melanoma
caused by:
Malignant tumour of melanocytes
- -> Melanocytes become abnormal
- -> Atypical cells and architecture
caused by:
UV exposure
Genetic factors
what is lentigo maligna
(Melanoma in situ)
- Proliferation of malignant melanocytes within the epidermis
- No risk of metastasis
- light / dark brown colors
- irregular shape
what is lentigo maligna melanoma
- there is superficial spreading MM
- Lateral proliferation of malignant melanocytes
- Invade basement membrane
- Risk of metastasis
How would you diagnose superficial spreading malignant melanoma?
ABCD rule
- Asymmetry
- Border irregular
- Colour variation (dark brown-black)
- Diameter >0.7mm and increasing
- Erythema
what is nodular malignant melanoma?
- grows downwards
- bad prognosis
- Vertical proliferation of malignant melanocytes
- risk of metastasis
–> sometimes accompanies with spreading melanoma as well
What is Acral lentiginous melanoma
- melanoma of palms / soles
