epithelial membrane antigen


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epithelial membrane antigen (EMA),

a heavily glycosylated, 70-kD protein complex, first isolated in human milk fat globulin; this antigen is present in a variety of glandular epithelia, especially in breast carcinoma cells but may also be seen in cultured fibroblasts, lymphoid cells, and some stromal cells. Immunohistochemical staining may aid in tissue diagnosis.

epithelial membrane antigen

A 265–400-kD transmembrane glycoprotein found in milk-fat globule membranes.

Normal expression
Normal epithelia and perineurial cells.

Abnormal expression
Neoplastic epithelia and perineurial cells, meningioma, mesothelioma, mesenchymal tumours, some lymphomas, choroid plexus, arachnoid granulation, epithelioid histiocytes, anaplastic large cell lymphomas.

ep·i·the·li·al mem·brane an·ti·gen

(EMA) (ep'i-thē'lē-ăl mem'brān an'ti-jen)
A heavily glycosylated, 70-kD protein complex, first isolated in human milk fat globulin; this antigen is present in a variety of glandular epithelia, especially in breast carcinoma cells, but may also be seen in cultured fibroblasts, lymphoid cells, and some stromal cells. Immunohistochemical staining may be used as a diagnostic aid in tissue diagnosis.
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References in periodicals archive ?
The use of immunohistochemistry in distinguishing reactive from neoplastic mesothelium: a novel use for desmin and comparative evaluation with epithelial membrane antigen, p53, platelet-derived growth factor-receptor, P-glycoprotein and Bcl-2.
In two-thirds of all cases, sinonasal NEC stains for epithelial markers such as low-molecular-weight cytokeratins and epithelial membrane antigen.
The use of immunohistochemistry in distinguishing reactive from neoplastic mesothelium:a noveluse for desmin and comparative evaluation with epithelial membrane antigen, p53, platelet-derived growth factor-receptor, P-glycoprotein and Bcl-2.
The advent of IHC, with its enhancement by antigen retrieval techniques, and the ability to demonstrate cellular proteins such as vimentin, cytokeratin, and epithelial membrane antigen have revolutionized the histopathologic diagnosis of SS with formalin-fixed, paraffin-embedded tissue sections.
Renal cell carcinoma is usually positive for CD10 and epithelial membrane antigen.
Epithelioid sarcoma almost always displays epithelial membrane antigen, a feature only occasionally seen in cutaneous angiosarcomas.
Both spindle and epithelial cells express low- and high-molecular-weight cytokeratins and epithelial membrane antigen, but only spindle cells express vimentin and bcl-2.
Negative stains included c-kit, placental alkaline phosphatase, epithelial membrane antigen, and [alpha]-fetoprotein.
2, AE1/AE3, and 34[beta]E12), epithelial membrane antigen, carcinoembryonic antigen, carbohydrate antigen 19.
The benign syringocystadenoma papilliferum has been reported to show carcinoembryonic antigen and epithelial membrane antigen expression at the apical portion of the luminal cells as well as CK7 positivity in the luminal cells, whereas the basal cells express other keratins, such as CK5/6 and CK14, with patchy smooth muscle actin staining.
Immunohistochemistry for S-100 protein (dilution: 1:100) (figure 3) and neuron-specific enolase (dilution: 1:50) showed strong positivity in the tumor cells but was negative for epithelial membrane antigen (dilution: 1:50) and glial fibrillary acid protein (dilution: 1:5,000).
Epithelial membrane antigen (EMA) may be used in conjunction with keratins; however, it is not specific to epithelial differentiation and may be expressed in normal and neoplastic hematolymphoid cells including plasma cells and anaplastic large cell lymphomas.