Stains & CD markers
Epithelial membrane antigen (EMA)


Topic Completed: 13 December 2021

Minor changes: 13 December 2021

Copyright: 2002-2022, PathologyOutlines.com, Inc.

PubMed Search: EMA[TI] pathology full text[SB]

Heather I-Hsuan Chen-Yost, M.D.
Tatjana Antic, M.D.
Page views in 2021: 32,151
Page views in 2022 to date: 1,615
Cite this page: Chen-Yost HI, Antic T. Epithelial membrane antigen (EMA). PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/stainsema.html. Accessed January 19th, 2022.
Definition / general
Essential features
  • EMA (aka MUC1) a glycoprotein that provides barrier function
  • Overexpression is common in malignancies and leads to tumorigenesis
  • Immunohistochemical stain is positive in most carcinomas, often used alongside other cytokeratin stains
  • For noncarcinomas, EMA is useful to distinguish meningioma, some hematopoietic tumors and malignant mesothelioma
Terminology
Pathophysiology
  • Normal
    • Localized to the apical membranes and provides barrier function (Nat Rev Cancer 2009;9:874)
      • Blocks cell to cell and cell to extracellular matrix interactions
    • Inhibits formation of E-cadherin / beta catenin complex (Ann Pathol 2006;26:257)
  • Abnormal (Trends Mol Med 2014;20:332)
    • Overexpressed and loses cell polarity
      • Redistributed in cell surface and cytoplasm
    • Abnormal distribution leads to expression of PDGFA
      • Promotes proliferation and invasion of cells
    • Interacts with and stabilizes HIF1α
      • Enhances glucose uptake genes
    • Induces expression of proangiogenic factors (CTGF, PDGFB, VEGFA)
    • Upregulates expression of inducers that lead to destabilization of adherens junctions and leads to cytoskeleton rearrangements (Oncogene 2011;30:1449)
      • Facilitates basement membrane invasion
Clinical features
Interpretation
Uses by pathologists
Prognostic factors
Microscopic (histologic) images

Contributed by Jijgee Munkhdelger, M.D., Ph.D., Andrey Bychkov, M.D., Ph.D. and Ihab Hosny, M.D.
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Epithelioid mesothelioma immunoprofile

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Epithelioid mesothelioma, EMA

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Cervix, adenoid cystic carcinoma



Cases #219, 150, 48 and 69
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Bladder, high grade urothelial carcinoma

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Heart, synovial sarcoma

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Kidney, papillary carcinoma, solid

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Scrotum, epithelioid sarcoma

Virtual slides

Images hosted on other servers:

Appendix - goblet cell carcinoid: EMA highlights epithelial differentiation

Brain - angiomatous meningioma: EMA+ (membranous staining)


Breast - invasive ductal carcinoma: EMA+ (cytoplasmic staining)

Ovary - yolk sac tumor: EMA-

Cytology images

Contributed by Jijgee Munkhdelger, M.D., Ph.D. and Andrey Bychkov, M.D., Ph.D.
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Epithelioid mesothelioma, pleural effusion (cell block)

Positive staining - normal
Positive staining - disease
Negative staining
Sample pathology report
  • Left frontal tumor, craniotomy and resection:
    • Meningioma, WHO grade 1 (see comment)
    • Comment: The histologic features fit well for a meningioma with fibroblastic features. EMA shows positive cytoplasmic staining in the spindle cells. There are no atypical features and mitoses are sparse. The MIB1 labeling is low (less than 4%).
Additional references
Board review style question #1

Which of the following immunohistochemical stains best differentiates meningioma from schwannoma?

  1. AE1 / AE3
  2. CD34
  3. EMA
  4. MelanA
  5. S100
Board review style answer #1
C. EMA. Warning: EMA can highlight the perineural fibroblasts in schwannomas but is not positive within the mass. AE1 / AE3 is not typically positive in meningiomas. CD34 is better for differentiating solitary fibrous tumors from meningioma and is typically negative in schwannoma. MelanA differentiates meningioma from melanoma. MelanA is negative in most schwannomas. S100 can be positive in both schwannoma and in fibrous meningioma (J Neuropathol Exp Neurol 2017;76:289).

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Reference: Epithelial membrane antigen (EMA)
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