Ch. 1 - IHC Flashcards
What enzyme reaction forms the basis of IHC?
Diaminobenzidine method (DAB): Visualizes presence of enzyme-antibody-antigen complex fixed to tissue as a stable brown product. 3-amino-9-ethylcarbazole (AEC) can be used for red staining (does not archive as well).
CK polyclonal keratin (pankeratin)
Polyclonal cocktail that offers greater sensitivity than AE1/AE3.
p63
Expressed in basal and spinous cells of epidermis, germinative cells of sebaceous glands, and myoepithelial cells of sweat glands.
Useful in distinguishing cutaneous origin of spindle cell neoplasms.
CK7
In general, a marker of non-GI adenocarcinomas. Also marks Paget’s.
CK20
Marker of GI adenocarcinoma and merkel cell carcinoma (paranuclear dotting).
AE1/AE3
High and low weight keratins. Stains all epithelial tumors as well as epithelioid sarcoma, synovial sarcoma, and mesothelioma.
CAM5.2
Detects LWMK of glandular neoplasms but not epidermis. Marks Paget’s.
CDX2
Marker of intestinal adenocarcinoma (usually metastatic CRC)
EMA
Highlights normal sebaceous and sweat glands. Positive in sebaceous, squamous cell carcinomas and Paget’s. Negative in BCC.
CEA
Marks sweat glands. Positive in most adenocarcinomas…
Adipophilin
Expressed in lipid droplets of sebaceous and xanthomatous lesions.
Can distinguish sebaceous carcinoma from SqCC/BCC
Ber-EP4
Marks epithelia except those undergoing squamous differentiation.
Positive in BCC, not SqCC.
Desmin
SMA
Desmin: Stains skeletal and most smooth muscle (not vascular smooth muscle)
SMA: Stains smooth muscle, including vascular smooth muscle (and glomus cells)
CD34
Marker of vascular endothelium and hematopoietic progenitor cells.
Positive in DFSP but not DF. Positive in spindle cell, sclerotic fibroma, SFT, and many others.
Factor XIIIa
Highlights dermal dendritic cells.
Positive in DF but not DFSP. Positive in fibrous papule of the face.
CD31
More specific vascular marker than CD34
D2-40 (podoplanin)
Lymphatic endothelial marker.
For detecting LVI and mets (nonreactive vs primary)
UEA (Ulex europeus agglutinin)
Binds vascular endothelium
GLUT1 (glucose transporter)
Expressed in endothelial cells with blood-tissue barrier function.
Positive in infantile hemangiomas (but not AVMs), also stains perineural cells.
Vimentin
Stains almost everything but epithelium.
General marker of sarcomas and excludes most carcinomas (except synovial sarcoma and rare spindle cell carcinomas)
S100
Neural-crest and some mesenchymal lines. Melanocytes, langerhans cells, sweat glands, neural tissue, myoepithelial cells…
Useful in ddx of spindle cell neoplasms
S100A6
Stains melanocytes, schwann cells, langerhans cells, and dermal dendrocytes.
Reactive in atypical fibroxanthomas and many other cutanoeus spindle cel neoplasms.
HMB-45
Premelanosome marker. Lost with normal descent & maturation into the dermis.
Lost in blue nevi. Does not stain desmoplastic melanoma reliably.
Melan-A, Mart-1
Stains same epitope in melanocytic lesions.
Does not stain desmoplastic melanoma reliably.
p75 (nerve growth factor receptor)
Early NC marker, expressed in type C (spindled) melanocytes and schwann cells.
Sensitive marker for spindle cell and desmoplastic melanoma.
MITF
Nuclear melanocytic marker, also positive in cellular neurothekomas.
Sox-10
Nuclear marker of schwann cells and melanocytes. Sensitive marker of melanoma (all types).
Neuron-specific enolase
Positive in neuroendocrine cells, neurons, and many other tumors… “non-specific enolase”
Synaptophysin / Chromogranin
Positive in neuroendocrine cells and merkel cell carcinoma.
CD45Ra (LCA)
CD45Ro (UCHL-1)
Leukocyte common antigen: General marker of hematolmphoid differentiation, including precursors
UCHL-1: Mature T-cells
CD20
B-cell antigen (often lost in plasma cells).
CD10 (CALLA)
Common acute lymphoblastic leukemia antigen: Early B-cell marker.
For B-cell neoplasms, periadnexal mesenchymal cells, atypical fibroxanthomas, renal cell carcinoma, many others.
CD79a
Plasma and B-cell marker
CD139 (syndecan-1)
Plasma cell marker
CD3
CD4
CD8
Pan-T-cell marker.
T-helper marker
Cytotoxic T-cell marker.
CD5
Pan-T-cell marker like CD3, but aberrant loss in CTCL is common.
Also positive in mantle cell lymphoma and CLL.
CD30 (Ki-1, BERH2)
Marks Reed-sternberg cells, activated lymphocytes of ALCA and lymphomatoid papulosis.
Also positive in scabies and chronic tick bites?
CD7
Immature T-lymphocyte antigen, most commonly lost antigen in T-cell lymphomas.
CD56
Marker of NK cells. Stains blastic plasmacytoid dendritic cell neoplasm (blastic NK/T-cell lymphoma).
CD68 (KP1)
Reactive in virtually all monocyte/macrophage cells.
CD163
Reactive in monocytes and macrophages
CD123
Marker of plastmacytoid dendritic cells (positive in blastic plasmacytoid dendritic cell neoplasm)
Myeloperoxidase
Granules of neutrophilic myeloid cells. Marker for AML
ALK-1
Anaplastic lymphoma kinase: t(2;5) in most ALCAs except for primary cutaneous ones. Negative is poor…
CD117 (c-Kit)
Expressed in mast cells nad melanocytes.
Decrease in nevi and primary melanoma in the dermis. Altogether lost in metastasis.
Langerin (CD207)
Surrogate marker for presence of Birbeck granules in Langerhans cells.
CD43 (Leu-22)
Pan-T-cell marker.
Aberrant co-expression with CD20 strongly suggests B-cell lymphoma.
BCL2
Anti-apoptotic oncogene usually for B-cell neoplasms.
Also stains BCC (entirely) and trichoepitheliomas (outermost layers).
MUM-1
Expressed in plasma cells, activated T-cells, and some germinal-center cells.
Also expressed in melanocytes.
CD21 / CD23
Follicular dendritic cell marker.
Residual follicle in lymphoma.
BetaF1
Identifies alpha/beta T-cells?
Ki-67
Non-specific nuclear proliferation marker expressed in all phases of the cell cycle.
pHH3
Mitotic marker that only stains M-phase cells.
