Myoepithelial cells are normal constituent of the salivary acini and smaller ducts, and are found between the epithelial cells and the basement. Myoepithelial cells are true epithelial cells that form desmosomes and Smears from myoepithelial carcinoma may show spindle/plasmacytoid cells but an. There is increasing evidence that the myoepithelial cells also play a key role in the organizational development of the mammary gland, and that.


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First identified as a neurogenic cell-associated protein, but it also has been found in myoepithelial cells of normal myoepithelial cells glands and pleomorphic adenoma, possibly in relation to the filamentous component in the myoepithelial cells. Cytokeratin 4—6 and cytokeratin 14 identify myoepithelium in the normal gland.

Vimentin, an intermediate filament is found in cells of mesenchymal origin and neuroectodermal origin. It is closely related to the myofilaments and cell adhesions.

Myoepithelial Cells: Their Origin and Function in Breast Morphogenesis and Neoplasia

This suggests that myoepithelial cells in pleomorphic adenoma and myoepitheliomas may be capable of expressing both ectodermal and mesenchymal cytoskeletal filaments during neoplastic transformation.

Fibronectin and laminin Two types of glycoprotein are identified in the extracellular matrix in the epithelial cells. They are also found in the cytoplasm and the cell membranes of the myoepithelial cells in the myoepitheliomas.

Fibronectin is also present in the myxoid and microcystic areas of the myoepitheliomas. Elastin Appears globular as myoepithelial cells as diffusely spread in the myoepitheliomas especially between the plasmacytoid cells and in myxoid cells.

Muscle-specific Actin and Myosin, Glial Fibrillary Acidic Protein Muscle-specific actin, cytokeratin 14, vimentin and glial fibrillary acidic protein are diagnostic markers of neoplastic myoepithelial cells. In normal salivary glands, p63 was expressed in the nuclei of myoepithelial and basal duct cells.

Myoepithelial cells in pathology

Processes of myoepithelial cells protruded into the interstitial places, giving rise to bizarre appearances. This tumor is considered as monomorphic due to lack of myxochondroid component. It can be differentiated from pleomorphic adenoma by lack of myoepithelial differentiation.

Presence of hyalinized matrix in basal cell adenoma gives an evidence of myoepithelial cell myoepithelial cells. Solid, cribriform and tubular. Some researchers believe that this neoplasm originates from the reserve duct cell either excretory or intercalated duct.

Each cell consists of a cell body from which processes radiate and embrace the secretory unit. Myoepithelial cells have contractile functions.

The CK 5 and 14 have an important role in the cytoarchitecture of myoepithelial cells, as they are connected to desmosomes and hemidesmosomes which mediate the connection of myoepithelial cells to adjacent cells and the underlying BM, respectively 8 The plasma membrane of myoepithelial cells is characterized by the presence of pinocytic vesicles 17which are now classified as caveolae Interestingly, Hamperl in his review suggested that myoepithelial myoepithelial cells may control transport and metabolism of molecules between luminal epithelial cells and the basement membrane The myoepithelial cell cytoplasm is filled with actin and myosin, which are responsible for the contractile phenotype mediated by oxytocin during lactation 20 Myoepithelial cells contribute significantly to basement membrane production by expression and deposition of fibronectin, collagen IV, nidogen, and the bioactive laminins 911 They also possess BM receptors, including integrins, which mediate cell—BM attachment and occasionally cell—cell interactions Furthermore, a number of tumor suppressor proteins, including p63, p73, sigma, maspin, and Wilms Tumor have been preferentially detected in myoepithelial cells 27 — 29consistent with the apparent endogenous tumor suppressor function of myoepithelial cells.

It has been suggested that these minimally or partially differentiated myoepithelial cells may affect the function and biological behavior of adjacent epithelial cells 28highlighting myoepithelial cells need to better understand the origin and lineage development of myoepithelial cells in the human breast.

The cornerstone for successful studies concerning lineage relationships and the function of various cell types within the breast was the introduction and improvement of cell separation techniques.


In order for researchers to unequivocally identify myoepithelial precursor cells, it has been necessary to separate different cell lineages from the human breast and culture them myoepithelial cells under conditions that maintain their phenotypic marker profile observed in situ.

We will be updating all our staging articles VERY soon in light of these changes. Normally, the presence of myoepithelial cells in a histological workup is an inconspicuous finding.

However, presence of reduced or under-stress myoepithelial cells in the context of a suspected breast cancer can be of concern, and may indicate a transition to infiltrating and possibly invasive status.

I have created two new versions of this page with more myoepithelial cells information on Myoepithelial and another one on Cell Markers.