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Markers of melanocytic
tumours
Markers of
melanocytic tumours
Tomas Seidal, MD, PhD
Länssjukhuset i Halmstad
Chairman of NordiQC
¾ Basic facts
¾ Antibodies well known to most,
most, for many
years
¾ Well recognized diagnostic situation
¾ NordiQC experience this far
¾ Discussion
Markers of melanocytic
tumours
¾
There are several markers, reported to stain
positively in melanoma cells and cells of other
naevocellular tumours:
tumours:
z
z
z
z
z
z
z
Protein ss-100
Vimentin
Microphtalmia transcription factor
Tyrosinase
HMB 45
Melan A
C-kit (CD 117) and many others
Markers of melanocytic
tumours
¾
Melanocytic tumours are virtually never positive
for:
z
z
z
z
¾
And very rarely positive for:
z
z
z
Markers of melanocytic
tumours
¾ In practical immunohistochemistry,
immunohistochemistry,
however,
however, there are only few markers that
are used,
used, because of their sensitivity
and/or specificity and because they are
well known and quite easy to use
z
z
z
Protein ss-100
Melanoma Specific Antigen, (MSA) HMBHMB-45
Melan A
Cytokeratin 7 and 20
Desmin
CD 20
Chromogranin
Cytokeratin coctails
Actin
EMA
Markers of melanocytic
tumours
¾ Protein ss-100
z
z
z
z
Dimeric 21kDa protein
Two subunits:
subunits: alfa and beta
May be found in the nucleus,
nucleus, the cytoplasm
and the cytoplasmic membrane
Present in, for instance,
instance, glial tissue,
tissue, Schwann
cells, melanocytes,
melanocytes, myoepithelial cells and
some glandular epithelium (sweat glands,
glands,
kidney,
kidney, breast,
breast, striated muscle,
muscle, chondrocytes
and FDC
1
Markers of melanocytic
tumours
¾
Protein ss-100 continued
z
Markers of melanocytic
tumours
¾
Present in >90 % of
•
•
•
•
•
•
•
•
Protein ss-100 continued
z
Markers of melanocytic
tumours
¾
Protein ss-100 continued
z
Present in <50 % of
•
•
•
Granulosa cell tumours
Adenocarcinomas of breas
and several others
Thus,
Thus, ss-100 is sensitive but very unspecific
for melanocytic neoplasms.
neoplasms.
Protein ss-100 may also be of importance in
tumour diagnosis not involving melanomas
z
z
z
z
z
Present in junction nevi,
nevi, compound nevi
(epidermal part, weaker in dermal part), blue
nevi,
nevi, dysplastic nevi,
nevi, Spitz
Rhabdomyoma
Angiomyolipoma
Clear cell sarcoma
and some other fairly uncommon neoplasms
and other conditions
PNET
Clear cell sarcomas
Rhabdomyosarcomas
Chondroid tumours
Sweat gland carcinomas
Thyroid carcinomas
Renal cell carcinoma
Serous and endometroid ovaraian tumours
Monocytic/
Monocytic/monoblastic leukemias
Markers of melanocytic
tumours
¾
MelanomaHMB-45
Melanoma-specific antigen (MSA) HMBz
z
z
Markers of melanocytic
tumours
¾ MelanomaHMB-45
Melanoma-specific antigen (MSA) HMB-
Present in >50<90 % of
•
•
•
•
•
•
•
•
•
Astrocytoma,
Astrocytoma, glial tumours
Benign and malignant Scwannomas,
Scwannomas, neurofibromas
Granular cell tumours
Myoepithelial tumours
Polymorphous low grade adenocarcinoma
Langerhan’s cell histiocytosis,
histiocytosis, xanthogranulomas
Chordomas
Lipomas,
Lipomas, liposarcomas
The melanomamelanoma-specific antigen is a poorly
characterized oligosaccharide,
oligosaccharide, identified by
the monoclonal antibody HMBHMB-45
Present in the cytoplasm of activated and
immature melanocytes,
melanocytes, but not in mature
melanocytic cells.
Positive in 6060-90 % of melanomas;
melanomas; not in
spindlespindle-cell/desmoplastic
cell/desmoplastic variants
Markers of melanocytic
tumours
¾ MelanomaHMB-45
Melanoma-specific antigen (MSA) HMBz
z
z
Considerably more specific than s-100
Less sensitive than s-100
May play a role in rare instances of differential
diagnosis in nonnon-melanocytic neoplasms
2
Markers of melanocytic
tumours
¾
Melan A
z
z
z
z
Also called MARTMART-1 (Melanocyte
(Melanocyte antigen recognized
by TT-cells)
2020-22 kDa protein associated with endoplasmatic
reticulum and melanosomes
Expressed in all normal melanocytes and melanocytic
cellcell-lines
Also detected in steroidsteroid-producing cells (adrenal
(adrenal
cortex, Leydig cells, granulosa and theca cells) due to
cross reaction since the MARTMART-encoding gene is not
detected in these cells
Markers of melanocytic
tumours
¾ Melan A
z
z
z
z
Markers of melanocytic
tumours
¾ Melan A
z
z
z
z
z
z
z
Positive in other neoplasms of melanocytic
origin,
origin, such as :
Benign nevi,
nevi, Spitz, blue nevi
Clear cell sarcoma
Melanotic Schwannoma
PEComa (perivascular epithelioid cell tumour)
Angiomyolipoma
SteroidSteroid-producing tumours
Markers of melanocytic
tumours
¾ Melan A
z
z
z
z
Markers of melanocytic
tumours
¾
Immunohistochemistry using melanocytic
markers is of particular value in the diagnosis in
cases of:
z
Cutaneous melanocytic tumours with an unusual
appearance
• Signet ring cell melanoma
• Spindle cell or desmoplastic melanoma
z
Melanocytic tumours with an unusual localization (and
sometimes also an unusual appearance)
appearance)
• Mucosal
• Nasal
Expressed in 8080-100 % of melanomas
Almost 100 % expression in primary
cutaneous and mucosal melanoma
Less often and weaker expressed in
metastatic lesions
Desmoplastic melanomas may be negative
Is a highly specific and sensitive marker for
melanocytic differentiation
More sensitive than HMBHMB-45
Considerably more specific than s-100
Appears to be the most valuable marker for
melanoma
Markers of melanocytic
tumours
¾ Immunohistochemistry using melanocytic
markers is of particular value in the
diagnosis in cases of:
z
z
z
Metastatic lesions with no known primary
tumour
To confirm metastatic melanoma/
melanoma/melanocytic
tumours -sentinel node
As a help in the distinction between benign
and malignant lesions??
3
Melanoma in rectal mucosa
Metastatic melanoma in
duodenum
S-100
CK
Melan
Metastatic melanoma in
duodenum
Metastatic melanoma in
duodenum
Protein s-100
Melan A
Melanoma in nasal mucosa
Melanoma in the anal mucosa
S-100
Melan A
4
Melanoma in the anal mucosa
Malignant melanoma in the
maxillary sinus
EMA
EMA
CK
S-100
Melan A
S-100
Melan A
Metastatic melanoma in the
jejunal wall
The NordiQC experience
¾ Run 7, 2003
¾ 63 labs submitted s-100 stainings
¾ 66 labs submitted MSA stainings
¾ 35 labs submitted Melan A stainings
The NordiQC experience
¾ MultiMulti-tissue block,
z
z
z
z
z
ss-100 staining
Malignant melanoma of the bowel
Brain tissue
Malignant melanoma of the testis
Appendix
Blue nevus
The NordiQC experience
¾ Criteria for the ss-100 staining as optimal:
z
z
Strong and distinct nuclear and cytoplasmic
staining reaction in the tumour cells of
malignant melanoma and the nevus
Glial cells, Schwann cells, fat cells, reticulom
cells including epidermal Langerhan’s cells
should also be demonstrated.
demonstrated.
5
The NordiQC experience
¾ Results of the assessment of ss-100
stainings
z
z
z
z
Optimal 19 (30%)
Good 26 (41%)
Borderline 10 (16%)
Poor 8 (13%)
The NordiQC experience
¾ S-100 staining
¾ What characterized the submitted
protocols when the staining results were
optimal or good?
z
z
z
Polyclonal ab Z0311
Sufficient concentration of the ab
Sufficient prepre-treatment (HIER or enzymatic)
enzymatic)
The NordiQC experience
The NordiQC experience,
experience, ss-100
¾ MultiMulti-tissue block,
z
z
z
Normal appendix
z
z
MSA staining
Malignant melanoma of the bowel
Granulosa cell tumour
Malignant melanoma of the testis
Adrenal gland
Blue nevus
Normal app, HM
The NordiQC experience
¾ Criteria for the MSA staining as optimal:
z
z
Strong and distinct cytoplasmic staining
reaction in the tumour cells of malignant
melanoma and the nevus
No staining reaction seen in other cells.
The NordiQC experience
¾ Results of the assessment of MSA
stainings
z
z
z
z
Optimal 30 (45%)
Good 19 (29%)
Borderline 13 (20%)
Poor 4 (6%)
6
The NordiQC experience
¾
¾
MSA staining
What characterized the submitted protocols
when the staining results were optimal or good?
z
z
z
Sufficient concentration of the ab
Sufficient prepre-treatment (HIER or enzymatic)
enzymatic)
The use of a nonnon-biotin based detection system or
efficient biotin blocking
The NordiQC experience
¾ MultiMulti-tissue block,
z
z
z
z
z
The NordiQC experience
¾
Criteria for assessing the Melan A staining as
optimal:
z
z
z
Strong and distinct cytoplasmic staining reaction in
the normal melanocytes,
melanocytes, the tumour cells of
malignant melanoma and the nevus
If mAb was used,
used, a distinct staining of the granulosa
cell tumour and adrenal cortex cells should be seen
No staining reaction seen in other cells.
The NordiQC experience
¾
¾
Melan A staining
Malignant melanoma of the bowel
Granulosa cell tumour
Malignant melanoma of the testis
Adrenal gland
Blue nevus
The NordiQC experience
¾ Results of the assessment of Melan A
stainings (35! labs submitting stainings)
stainings)
z
z
z
z
Optimal 14(40%)
Good 10 (29%)
Borderline 8 (23%)
Poor 3 (8%)
The NordiQC experience
Melan A
Melan A staining
What characterized the submitted protocols
when the staining results were optimal or good?
z
z
z
The use of HIER in TrisTris-EDTA pH 9, when using mAb
A103
Sufficient prepre-treatment (HIER or enzymatic)
enzymatic)
Sufficient concentration of the mAb
A
B
C
A.Blue nevus
B. Malignant melanoma
C. Malignant melanoma
D. Granulosa cell tumour
E Adrenal cortex
D
E
7
Suggestions/conclusions I
Benign nevus, Mel A
¾ The antibody panel för melanocytic
differentation should contain
What can be suggested or concluded?
z
z
z
Suggestions/conclusions II
¾ The antibody panel för melanocytic
differentation may also contain
z
Microphtalmia transcription factor
• A nuclear marker
• Expressed in desmoplastic variants
z
When appropriate
• Vimentin
• Ki 67
always positive in melanoma
may contribute in some cases
Protein ss-100
Melan A
for its sensitivity
for its specificity
In fact:
sfact: a tumour cell population that is
s100+/Mel A+ is very likely to be melanocytic
Suggestions/conclusions III
¾ The NordiQC experience clearly indicates
that improvements are needed and that
external quality control is very important in
immunohistochemistry to achieve and
maintain high standards in routine
diagnostic work
Thanks for listening
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