B6-030 CBCL Skin Cancers Flashcards
brown/black melanin
eumelanin
yellow/orange melanin
pheomelanin
[…] skin color is impacted by solar radiation, UVR, and endocrine system
facultative
are differences constitutive skin color due to the number of melanocytes?
no
what amino acid is necessary for pheomelanin synthesis?
cysteine
TRP1 and DCT contribute to the synthesis of […] melanin
eumelanin
the expression of […] is a major determinant for blue/brown eye color
OCA2
**tyrosinase trafficking/processing enzymes
lower MC1R signaling results in
more pheomelanin and lighter skin
higher MC1R signaling results in
relatively more eumelanin and darker skin
loss/significantly reduced function of MC1R is associated with
red hair phenotype
induces MITF, which activates expression of melanin synthesizing enzymes
a-MSH
MC1R agonist [2]
a-MSH
ACTH
MC1R antagonist
Asip
inhibits eumelanin and promotes expression of genes for pheomelanin
Asip
activates DNA repair signaling
MC1R
**deficits increase risk of skin cancer
how do deficits in MC1R signaling cause an increased risk of skin cancer? [2]
- decreased production of protective eumelanin
- less activation of DNA repair pathways
sunburn is mostly caused by UV[…]
UVB
UVB results in lesions of […] in DNA
pyrimidine dimers
delayed tanning (sunburn) damages keratinocytes and causes the secretion of […], which stimulate eumelanin production
cytokines and chemokines
**mediated by a-MSH and ACTH
does sunscreen protect from UVA or UVB?
UVB
at high SPF values, protection [does/does not] increase proportionally
does not
are current recommendations promoting UV protection for melanoma prevention in skin of color supported by current research?
no, there is little evidence to support this
**however, AAD recommends everyone use sunscreen regardless of skin tone
[keratinocytes or melanocytes]
tend to be in stratum basale or even below stratum basale
melanocytes
[keratinocytes or melanocytes]
small, dark nucleus
light, fluffy cytoplasm
melanocytes
[keratinocytes or melanocytes]
cleft goes all the way around, or partly around nucleus with no intervening cytoplasm
keratinocyte
[keratinocytes or melanocytes]
found in stratum spinosum
keratinocytes
melanocytic tumors [3]
benign nevi
dysplastic nevus
malignant melanoma
melanocytic nevi located where the dermis and epidermis meet
junctional nevus
melanocytic nevi located in epidermis and dermis
compound nevus
melanocytic nevi located in dermis
dermal nevus
what is this?
dysplastic nevus
what is this?
malignant melanoma
keratinocytic tumors [5]
lentigo
seborrheic keratosis
actinic keratosis
squamous cell carcinoma
basal cell carcinoma
looks like “socks dipped in chocolate”
solar lentigo
white pores
seborrheic keratosis
feels like sandpaper
precursor to squamous cell carcinoma
actinic keratosis
spiky contours
squamous cell carcinoma
[…] carcinoma is pink
squamous cell
[…] carcinoma is blue
basal cell
dense red keratin with preserved nuclei
squamous cell carcinoma
basal cell carcinoma
occur due to mutations in the Hedgehog signaling pathway, most commonly PTCH1 or also P53
basal cell carcinoma
raised, rolled edges
basal cell carcinoma
therapy for metastatic or inoperable basal cell carcinoma [2]
anti- PD1 inhibitor
vismodegib, sonidegib (inhibit Hedgehog pathway)
premalignant cutaneous lesions that may progress to squamous cell carcinoma
actinic keratoses
[…] mutation is thought to occur early in the development of actinic keratosis
p53
treatment options for metastatic squamous cell carcinoma
chemotherapy
EGFR inhibitor (cetuximab)
anti PD1 (cemiplimab, prembolizumab)
constitutive activation of RAS or BRAF but growth arrest is mediated by CDK
benign nevi
nevi located in the dermo-epidermal junction
junctional nevi
nevi located partially in the dermis
compound
nevi located completely in the dermis
intradermal nevi
50% of patients with congenital […] will develop melanoma by age 60
dysplastic nevus syndrome
loss of CDKN2A is associated with [2]
dysplastic nevus syndrome
familial melanoma syndrome
activating mutations in NRAS/BRAF and inactivating mutations in CDKN2A/CDK4 [2]
dysplastic melanocytic nevus
melanoma
activating mutations in FGFR3
seborrheic keratoses
sudden appearance of several seborrheic keratoses
maybe due to TGF-a
Leser-Trelat sign
**commonly associated with GI adenocarcinomas
multiple, small seborrheic keratoses occurring in people of color
dermatosis papulosa nigra
benign finding, can be removed for cosmetic reasons
diagnostic steps for melanoma [3]
biopsy-depth of primary lesion
determine sentinel node involvement
staging studies
treatment for stage III melanoma BRAF +
BRAF/MEK inhibitor or anti PD-1
treatment for stage III melanoma BRAF -
one year anti PD-1 (pembrolizumab)
constitutive skin tone is determined by [2]
number, size, distribution of pigment granules in skin
relative amount of eumelanin and pheomelanin in melanosomes
solar UVR exposure contributes to […] skin tone
facultative
MC1R signaling activates [2]
expression of pigment synthesizing enzymes
DNA repair enzymes
[UVB or UVA]
most effective at producing erythema
UVB
[UVB or UVA]
penetrates into dermis
UVA
[UVB or UVA]
passes through glass
UVA
[UVB or UVA]
production of pyrimidine dimers on DNA
UVB
what causes sunburn at the cellular level?
release of inflammatory mediatiors
DNA damage triggers […] that produces the warmth, pain, and erythema of sunburn
inflammatory mediators
immediate pigment darkening in the hours following UVR exposure is caused by
redistribution and oxidation of melanin already present in melanosomes
aspects of mechanism that induce delayed tanning [2]
DNA damage and subsequent MCR1 activation and signaling
increased expression of enzymes responsible for pigment synthesis
what layer of skin are adipocytes found in?
hypodermis
what layer of skin is collagen found in?
dermis
what layer of skin are melanocytes found in?
epidermis-stratum basale
what layer of skin are hair follicles found in?
dermis
what layer of skin are keratinocytes found in?
epidermis
melanocyte nests located only in the epidermis
junctional nevus
melanocyte nests located in epidermis and dermis
compound nevus
melanocytes nests located in the dermis
dermal nevi
nevi that are lentiginous, broad, and mostly at the junction
dysplastic nevi
elongated rete pegs
melanin pigment in dermis within macrophages
spread out (lentiginous)
dysplastic nevi
asymmetric appearance with upward scatter of single melanocytes
melanoma
hyperpigmented rete pegs
“socks dipped in chocolate”
solar lentigo
solar lentigo are derived from
keratinocytes
characteristic “sand paper” feel
actinic keratosis
keratin pearls visible on histology
squamous cell carcinoma
blue nodules with palisading of tumor cells
basal cell carcinoma
has potential to progress to squamous cell carcinoma
actinic keratosis
a history of immunosuppression leads to an increased risk for
squamous cell carcinoma
edges that are shiny, slightly raised, rolled
basal cell carcinoma
pigmented nevi often have mutations in
BRAF/RAS
transcriptional silencing of […] is found in 1/5 of non-sun-exposed melanoma
PTEN
are solar lentigines cancerous precursors?
no
pearly white, skin colored nodule in light skinned people, more darkly pigmented in dark skin people
edges may be shiny, slightly raised, and rolled
basal cell carcinoma
ulcerated, tender pink papule with central crust
squamous cell carcinoma
precursor for squamous cell carcinoma
actinic keratosis
gray elastosis on histology is a feature of [2]
solar lentigo
actinic keratosis
keratin pearls on histology is a feature of
squamous cell carcinoma
upward sweep of individual cancer cells on histology is a feature of
melanoma
even when sunscreen is used properly, [….] can still result in sunburn
long enough exposure to sun
number of melanocytes [does/does not] determine skin pigment production
does not
MOA of PD-1 inhibitor (pembrolizumab)
killing of tumor cells by T cells
**normally PD-L1 binds to PD-1 on T cells inhibiting T cell mediated destruction of cancer cells
PD-1 inhibitors prevent the binding of PD-1L/PD-1, thus facillitating T cell mediated destruction of tumor cells
though UVA is “less damaging” than UVB, it can generate
ROS which can damage DNA
upward scatter of single melanocytes
melanoma
“socks dipped in chocolate”
solar lentigo
long rete pegs
singly spaced letiginous melanocytes
some melanin in dermis
dysplastic nevus
architecturally disordered junctional nests and lentiginous spread extending well beyond the dermal component
dysplastic nevus
describe the cell signaling pathway that promotes cell proliferation
RTK/RAS —> BRAF/MEK/ERK —> cyclin D1-CDK4/6
BRAFV600E mutation results in
constitutive activation of BRAF, regardless of RAS signaling. Results in constitutive activation of cell proliferation pathway
circular lamellae of keratin
SK (horn cysts)
blue nodules in the dermis
basal cell carcinoma
keratin pearls
squamous cell carcinoma
inactivating mutations in […] can occur in dysplastic nevi
CDKN2A or CDK4
congenital dysplastic nevi syndrome is associated with loss of […] gene
CDKN2A
required to maintain the ends of chromosomes
telomerase
overexpression of telomerase would result in
“replicative immortality”
telomerase maintains chromosome length. Usually once telomeres shorten to a certain length, the cell becomes senescent
describe the cellular events leading to tanning/sunburn
- formation of pryrimidine dimers
- release of inflammatory mediatiors and secretion of ligands for MC1R
SCC has […] risk of metastasis
low
in what layer of skin are melanocytes found?
epidermis
solar lentigines can develop into
SK
BRAF signaling promotes
cellular proliferation
via activation of cyclin dependent kinases
BCC has […] risk of metastasis
low
commonly occurs above the upper lip
basal cell carcinoma
commonly occurs below the lower lip
squamous cell carcinoma
waxy pink pearly nodules
commonly with telangiectasias
rolled borders
BCC
can appear as nonhealing ulcers with infiltrative growth/scaling plaque
BCC
associated with immunosuppresion, chronic nonhealing wounds, and arsenic exposure
SCC
commonly appears on face, lower lip, ears, hands
SCC
melanoma has […] risk of metastasis
high
S-100
melanoma
in melanoma, […] of tumor corresponds with risk of metastasis
depth
**Breslow thickness
often driven by activating mutation in BRAF kinase
melanoma
BRAF inhibitor
vemurafenib