Skin cancer Flashcards
List the 8 hallmarks of cancer:
- sustaining proliferative signalling
- evading growth suppressors
- activating invasion and metastasis
- enabling replicative immortality
- inducing angiogenesis
- resisting cell death
- avoiding immune destruction
- deregulating cell energetics
What is an oncogene?
an over-active form of a gene that positively regulates cell division
What is a proto-oncogene?
The normal, not yet mutated form of an oncogene.
What is a tumour suppressor?
inactive or non-functional form of a gene that negatively regulates cell division
What are thy two types of Non-Melanoma Skin Cancer?
Basal Cell Carcinoma
Squamous Cell Carcinoma
Why does Xeroderma pigemetosum increase the risk of skin cancer?
Genes involved in DNA repair are mutated
Chronic/long term exposure to UV radiation predisposes to ….
Squamous cell carcinomea
UV_ radiation penetrates deepest into the skin. It causes direct/indirect DNA damage by ______ guanosine.
UVA radiation
indirect damage
oxidising guanosine
UV_ causes direct DNA damage.
UVB radiation
What are the UVB-caused DNA lesions?
Pyrimidine dimers
Pyrimidine-pyrimidone photo products
How does UVA cause DNA damage?
Via oxidation of DNA bases
What is the characteristic UVA-induced mutation? What is the repair mechanism involved?
C -> A point mutation
Base excision repair
What is the signature mutation induced by UVB?
What is the repair mechanism?
TT -> CC
Nucleotide excision repair
Mutations in c-KIT, B-RAF and MEK, genes involved in the Ras/Raf/MAPK signalling pathways are encountered in what skin cancer?
familial Malignant Melanoma
Basal skin carcinoma and Squamous skin carcinoma arise from what cell type?
Keratinocytes
What is the ABCDE of melanoma diagnosis?
Asymmetry Border Colour Diameter Evolution
A slow-growing painless lump with central ‘rodent’ ulceration and visible blood vessels are characteristic of what skin cancer
Basal Cell Carcinoma
A hyperkeratotic (crusted) lump/ulcer, which grows relatively fast is indicative of what skin cancer?
Squamous Cell Carcinoma
What are Actinic Keratoses? What cancers do they develop into?
Precancerous skin lesions.
Squamous cell carcinoma
Basal cell carcinoma
What is Naevoid basal cell carcinoma (Gorlin’s) syndrome?
Autosomal dominant familila cancer syndrome
Mutations in PTCH1, a key component of the Hedgehog signalling pathway (induces cell proliferation genes) are common in what skin cancer?
Basal cell carcinoma
Melanoblasts migrate to skin from the _____ ____.
neural crest
Melanocytes are situated in the ____ layer of the epidermis.
basal layer
What are ephilides?
freckles
Actinic lentigines are linked to ____ and _____ _____. Also known as ____ ____
age
and UV exposure
liver spots
Blue naevi and halo naevi are malignant (T/F)
False
What is the progression of growth of acquired naevi throughout life?
- junctional naevi - in childhood
- Adolescence - compound naevi (clusters at DEJ and in dermis)
- Adulthood -
Intradermal naevi
Spitz naevi are usually benign (T/F)
true
What are the 4 main types of Malignant melanoma?
- Superficial spreading
- Acral/mucosal lentiginous
- Lentigo maligna
- Nodular
What is the characteristic feature of Nodular melanoma?
Rapid progression into the vertical growth phase
-there is no initial containment to the epidermis
What is the main indicator of melanoma prognosis?
Breslow depth - vertical depth of the tumour
pTis (in situ) to pT4
What are the novel drug treatments of malignant melanoma metastases?
B-RAF and MEK inhibitors.
Seborrhoeic keratosis is a benign proliferation of epidermal keratinocytes (T/F)
True
The appearance of seborrhoeic keratosis is often described as ___ __
stuck on
The risk of metastasis of Basal Cell Carcinomas is low/high.
Low
- almost never metastasises
Telangiectatic vessels are characteristic of what slow-growing tumour?
nodular Basal cell carcinoma
What are the precursor lesions of Squamous Cell Carcinoma? (3)
- Bowen’s disease
- Actinic keratosis
- Viral lesions
What is Bowen’s disease? What’s it morphology?
In-situ displasia of keratinocytes.
It forms a scaly plaque with irregular borders.
Where are Bowen’s disease lesions usually found?
Legs
Where are Actinic keratoses usually found?
Sun-exposed areas, such as scalp, face, hands.
What pathogen is commonly associated with penile dysplasia?
HPV
Merkel cell (primary small cell neuroendorcine) carcinoma tends to have good prognosis. (T/F)
False
-very aggressive
If to widespread for surgery, ______ can be used to treat BCC
phototherapy
Corticosteroids have an adverse effect on skin healing (T/F)
True
What are the 5 layers of the scalp?
Skin connective tissue aponeurosis loose connective tissue periosteum
What is the most commonly used anaesthetic used in surgery? What is it used with?
Lignocaine
With Adrenaline
What does adrenaline do in terms of anaesthesia?
Prolongs anaesthesia and reduces bleeding
-do not use in digits
Treatment for Malignant Melanoma?
Excision biopy
Define stages of skin cancer in terms of Breslow thickness.
Stage Tsi - melanoma in situ Stage T1 - <1mm thick Stage T2 - 1-2mm Stage T3 - 2-4mm Stage T4 - >4mm
How is sentinel node biopsy performed?
- Dye is injected at the site of the melanoma
- Biopsy is performed to verify which lymph nodes the dye moves to from the tumour
- Lymph nodes can then be excised
