Special Stains & Immunohistochemistry
Following is a brief list of immunoperoxidase (IP) reactions with descriptions of their common diagnostic use for your information. We have a comprehensive menu of special stains and IP reactions used in our practice. At the bottom of this page you will also find useful links to sites with more extensive information on tissue markers and staining.
Actin: These contractile proteins are classified as alpha (skeletal, cardiac, and smooth muscle), beta (cytoplasmic), and gamma (smooth muscle and cytoplasmic). It is expressed in smooth muscle neoplasms. Actin also helps distinguish invasive carcinomas from non-invasive/benign by showing the presence or absence of a myoepithelial layer.
Alpha-Fetoprotein: (AFP) is produced in normal fetal yolk sac, fetal and regenerating adult liver and fetal gastrointestinal epithelium. AFP is found in 75% of nonseminomatous germ cell tumors and is useful in detecting hepatocellular carcinomas (HCC) and germ cell neoplasms, especially yolk sac tumors.
Alpha-1-Antichymotrypsin: Useful in identifying atypical fibroxanthomas in skin and malignant fibrous histiocytomas in soft tissue.
BCL2: Proto-oncogene BCL2 encodes the BCL2 protein, which inhibits apoptosis. In B-cell infiltrate, reactivity with BCL2 indicates that the infiltrate is likely a follicular center cell lymphoma. This protein is also helpful in differentiating basal cell carcinomas from trichoepitheliomas.
Calponin: Calponin binds tropomyosin and F-actin and is thought to be involved in the regulation of smooth muscle contraction. The expression of calponin is a marker of the differentiated contractile phenotype of developing smooth muscle. The expression of calponin has also been demonstrated in myoepithelial cells helping to differentiate benign and malignant breast lesions.
CD3: The anti-CD3 reacts with most T-Cell lymphomas in fixed tissue and is very specific for T-cell derivation.
CD20: (B-Lymphocyte Surface Antigen B1) This antigen plays a role in the regulation of human B cell proliferation. It is found only on the surface of B-lymphocytes. CD20 is strongly positive on approximately 50% of lymphoblastic lymphoma-leukemia and almost all B-cell lymphomas.
CD30: Human CD30 (Lymphocyte Activation Antigen CD30) (KI-1 Antigen) is a member of the tumor necrosis factor (TNF) receptor family and was originally found on Reed-Sternberg cells of Hodkin's disease. This marker is reactive in activated T and B cells, large celll anaplastic lymphomas, Hodgkin's disease, and lymphomatoid papulosis.
CD31: CD31 is also known as platelet-endothelial cell adheion molecule typ 1. CD31 helps indentify endothelial cells, granulocytes, monocytes, and platelets. This marker is most often used to identify tumors of endothelial origin.
CD34: (Sarcoma/endothelial/MDS marker) The antigen CD34, a transmembrane glycoprotein present on progenitor cells and endothelial cells, is a very sensitive marker for endothelial differentiation. It is expressed by most angiosarcomas, almost all Kaposi's sarcomas, and all epithelioid hemangioendotheliomas.
CD45: (Leucocyte Common Antigen; LCA) This antigen is expressed on all cells of hematopoietic origin, except erythrocytes. The antibody labels neoplastic B and T cells in non-Hodgkin's lymphoma and in leukemias of B and T-Cell types. There are two subsets, CD45RA and CD45RO. CD45RA stains resting B cells and naïve T cells and CD45RO stains memory T cells.
CD56: (Leu-19)(NKH1)(Neural Cell Adhesion Molecule; NCAM) CD56 is a natural killer (NK) cell marker. CD56 is present on certain LGL leukemias, small cell lung carcinomas, neural-derived tumors, myelomas, and myeloid leukemias. It also may be used to stain a subset of agiocentric T-cell lymphomas.
CD68: (Histiocytes) This antibody binds to a wide variety of cell types in the macrophage family, including Kupffer's cells and macrophages in the spleen, lamina propria of the gut, lung alveoli and bone marrow. This antibody may be useful for the identification of myelomonocytic and histiocytic tumors. CD68 may also help distinguish malignant fibrous histiocytoma from other pleomorphic sarcomas.
CD138: (Syndecan-1) Stains all plasma cells and plasma cell lines. Various forms of Hodgkin's disease have also shown positive staining with this antibody.
CEA: (CD66e)(Carcino-Embryonic Antigen; CEA) is expressed in a variety of secretory tissues. It is a normal protein product of the goblet cells found in the small and large intestines. CEA is thought to play a role in the development and proliferation of some neoplasms. It is usefull in the distinction between adenocarcinoma and malignant mesotheliomas of the epithelial type. It can sometimes be useful in the diagnosis of metastatic adenocarcinoma, extramammary Paget's disease, and eccrine neoplasms.
Chromogranin: Chromogranin is distributed in the secretory granules of endocrine and neuroendocrine cells. It is used as a panendocrine marker since it is expressed by a majority of neuroendocrine tumors.
Desmin: This is an intermediate filament located in intercalated disks, Z-lines of cardiac muscle, and Z-lines of skeletal muscle. Skeletal, cardiac, and smooth muscle stain positive.
EMA: EMA is a glycoprotein found in secretory mammary cells. EMA antibody is helpful in the diagnosis of extramammary Paget's disease, eccrine neoplasms, and sebaceous carcinoma.
ER/PR: Estrogen receptors (ER) are cellular proteins that bind estrogens with a high affinity and specificity. The presence of progesterone receptors (PR) demonstrates an active ER mechanism for the induction of PR expression. The ER is an important regulator of growth and differentiation in the mammary gland. Presence of ER in breast tumors indicates an increased likelihood of response to anti-estrogen (e.g. tamoxifen) therapy.
Factor 8: (FVIII; skin tumor marker) Factor 8 is a complex of factor VIII-C (anti-hemophilic factor) and factor VIII-associated antigen (Von Willebrand factor). Restricted to endothelial cells and megakaryocytes.
Factor 13: (FXIII) This is a coagulation factor fond intracellularly in platelets, macrophages, megakaryoctes. It is also found in dendritic cells in connective tissues and therefore distinguishes dermatofibroma from dermatofibrosarcoma protuberans.
GFAP: (Glial Fibrillary Acidic Protein) GFAP is an antibody that detects astrocytes, Schwann cells, satellite cells, enteric glial cells and some groups of ependymal cells. This marker is mainly used to distinguish neoplasms of astrocytic origin from other neoplasms of the central nervous system.
HMB 45: HMB 45 is a component of premlanosome vesicles. HMB 45 stains identify fetal and neonatal melanocytes, junctional and blue nevus cells, and a majority of melanomas and other tumors showing melanocytic differentiation.
Kappa/Lambda: These are immunoglobulin light chains which are glycoproteins released by and present on the surface of mature B cells and plasma cells. Monoclonal Kappa and Lambda antibodies provide a sensitive method to aid in the diagnosis of lymphomas.
Keratin HMW: (34-Beta E12) (Prostate, basal cells) Keratin HMW is capable of recognizing all basic keratin. Therefore, it is a broadly reactive antibody staining most epithelia and their neoplasms, such as squamous cell carcinomas, ductal carcinomas, most notably those of the breast, pancreas, bile duct and salivary gland, transitional cell carcinomas of the bladder and nasopharynx, thymomas, and epithelioid mesotheliomas.
Keratin 7: This low molecular weight cytokeratin is expressed in Paget's disease of the breast and also extramammary Paget's disease. Several carcinoma types are positive and when combined in a panel of Keratin reactions, Keratin 7 can narrow a differential diagnosis considerably.
Keratin 20: CK20 is found predominantly in gastrointestinal epithelium and its tumors. CK 20 positive tumor cells are found in the vast majority of adenocarcinomas of the colon, mucinous ovarian tumors, transitional-cell and Merkel cell carcinomas and also in adenocarcinomas of the stomach, bile system and pancreas. Demonstration of CK-20 positive Merkel cells in a skin tumor favors a benign interpretation.
Ki-67: (MIB-1) Ki-67 is a nuclear nonhistone protein that is present in all stages of the cell cycle except G0. Constantly proliferating cells express Ki-67 during the entire cell cycle. Ki-67 is useful in estimating the growth fraction of both benign and malignant tissues.
MART-1: (Melanoma Antigen) Recognized by T cells, MART-1 is expressed by melanoma cells and recognized by CD8+ T cells. MART-1 has proved to be a sensitive marker for melanocytic nevi and melanoma. A possible use is the diagnosis of melanoma and monitoring of immunotherapy for patients with melanoma.
PSA: (Prostate Specific Antigen) This antibody reacts with prostatic secretory and ductal epithelium in both normal and neoplastic tissue. This antibody recognizes primary and metastatic prostatic neoplasms but not tumors of non-prostatic origin
S-100: The S-100 family is a group of calcium channel binding proteins. They are found on melanocytes, langerhans cells, dermal dendrocytes. May be found on lipocytes and cartilage cells. S-100 is the most sensitive marker for melanocytic tumors, both nevi and melanoma.
TTF1: (Lung and Thyroid primaries) Belongs to a family of transcription factors found only in lung, thyroid and diencephalons. Useful in the determination of primary versus metastatic carcinomas of the lung and thyroid.
Vimentin: A ubiquitous intermediate filament expression during embryonic development and retained in mesenchymal cells, fibroblasts, endothelial cells, macrophages, melanocytes and lymphocytes. Used as a generalized marker for mesenchymal tumors.
Following is a list of special stains and immunoperoxidase reactions processed by our laboratory. This is an ever-expanding list. If there are unlisted stains or IPs you are interested in ordering, please call our Histology department at (805) 541-1583.
Leukemia (MPO, NSE, PAS, Sudan)
Alcian Blue (pH 1.0) (pH 2.5)
Mallory's Aninline Blue
Melanin (Fontana Masson) (Bleach)
Argentaffin (Fontana Masson)
Argyrophil (Sevier Munger)
Calcium (Von Kossa)
Nerve (Sevier Munger)
Oil Red O (fat)
Giemsa (Helicobacter) (Mast)
Steiner (Helicobacter) (Spirochetes)
Trichrome (Gomori) (Masson)
Actin (smooth muscle)
Factor XIIIa (skin tumor marker)
Antichymotrypsin (for AFX)
BCL2 (reactive vs. follicular lymphoma; basal vs squamous cell Ca.)
BRST 2 (GCDFP)
Calretinin/CK 5,6 (chk mesothelioma)
Calponin (smooth muscle)
Kappa/Lambda light chains
CD 2/3/5/7/43/CD45RO (T-cell)
Keratin AE1-AE3 (Pan)
CD 4 (Helper T-cell)
Keratin HMW (34-Beta E12)/P63 (Prostate basal cells)
CD 8 (Supressor T-cell)
CD 15 (LeuM1)
Ki-67 (proliferating cell antigen)
CD 20/CD 30/CD 79A (B-cell)
CD 23 (CLL Dendritic)
CD 34 (sarcoma/endothelial/leukemia)/ Factor VIII
P504S (prostate carcinoma cells/PIN)
CD 45 (LCA)
P63 (prostate basal cells)
CD 56 (NK cell, small cell CA, neuroendocrine tumor)
Pituitary Panel (HGH, ACTH, Prolactin)
CD 68 (histiocytes)
PLAP (Placental Alk phos for tumors)
CD 117 (c-kit) (GI stromal tumors, mast cells)
CD 138 (plasma cells)
TTF1 (lung & thy primaries)
|E-Cadherin (breast tumor diff)|
Immunoquery Web Page
Pub Med Web Page