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 ?
Practical utility of insulin-like growth factor II mRNA-binding protein 3, glucose transporter 1, and epithelial membrane antigen for distinguishing malignant mesotheliomas from benign mesothelial proliferations.
The majority of germ cell neoplasms stain positively with placental alkaline phosphatase (PLAP) and negatively with epithelial membrane antigen (EMA).
Intense carcinoembryonic antigen immunoreactivity on the luminal surfaces (89%, 8 of 9 cases), cytokeratin (CK) 20/ CDX2 (caudal type homeobox 2) positivity (100%, 9 of 9 cases) (Figure 2), CK7 positivity (56%, 5 of 9 cases) (Figure 3), and epithelial membrane antigen positivity (22%, 2 of 9 cases) have been reported in the literature.
The tumor turned out to be positive for Cytokeratin and Chromogranin A and negative for Epithelial membrane antigen (EMA).
The spindle cells were negative for melanin A, HMB-45, epithelial membrane antigen, pankeratin, muscle actin, CD 117, low-molecular-weight keratin, high-molecular-weight keratin, CD34, CD5, factor VIIIa, and CD45/leukocyte common antigen.
15) Sebaceous cells are immunoreactive for epithelial membrane antigen.
The results of staining for cytokeratin (CK) 5/6, CK7, and epithelial membrane antigen were equivocal (figure 2, C).
The tumor showed patchy positivity for epithelial membrane antigen and cytokeratin.
Immunohistochemically, the ductal component may stain positive for keratin, epithelial membrane antigen, and carcinoembryonic antigen.
Also, the cells of microglandular adenosis are characteristically positive for S100 protein (Figure 2, D) (21) and negative for epithelial membrane antigen.
Antibodies to epithelial membrane antigen (EMA), smooth-muscle actin (SMA), cytokeratin 8 (CK8), pancytokeratin (CK), vimentin, estrogen receptor (ER), prostate-specific antigen (PSA), C-erb2, CD68, carcinoembryonic antigen (CEA), and alpha 1-antitrypsin (AAT) were used with the avidin-biotin-peroxidase complex technique.
3% of cases), and Melan-A (positive in up to 85% of cases); epithelial markers, such as pancytokeratin (positive in up to 50% of cases) and epithelial membrane antigen (positive in up to 34.