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  • Expression of smooth muscle-specific proteins in myoepithelium and stromal myofibroblasts of normal and malignant human breast tissue.

Expression of smooth muscle-specific proteins in myoepithelium and stromal myofibroblasts of normal and malignant human breast tissue.

Proceedings of the National Academy of Sciences of the United States of America (1993-02-01)
D Lazard, X Sastre, M G Frid, M A Glukhova, J P Thiery, V E Koteliansky
ABSTRACT

The expression of several differentiation markers in normal human mammary gland myoepithelium and in certain stromal fibroblasts ("myofibroblasts") associated with breast carcinomas was studied by immunofluorescence microscopy of frozen sections. Several antibodies to smooth muscle-specific proteins (smooth muscle alpha-actin, smooth muscle myosin heavy chains, calponin, alpha 1-integrin, and high molecular weight caldesmon) and to epithelial-specific proteins (cytokeratins, E-cadherin, and desmoplakin) were used to show that myoepithelial cells concomitantly express epithelial and smooth muscle markers whereas adjacent luminal cells express only epithelial markers. The same antibodies were used to establish that stromal myofibroblasts exhibit smooth muscle phenotypic properties characterized by the expression of all the smooth muscle markers examined except for high molecular weight caldesmon. In addition, both myoepithelium and myofibroblasts show a significant degree of heterogeneity in smooth muscle protein expression. Thus, myoepithelial cells and stromal myofibroblasts are epithelial and mesenchymal cells, respectively, which coordinately express a set of smooth muscle markers while maintaining their specific original features. The dual nature of myoepithelial cells and the phenotypic transition of fibroblasts to myofibroblasts are examples of the plasticity of the differentiated cell phenotype.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Monoclonal Anti-Actin, α-Smooth Muscle, clone 1A4, ascites fluid
Sigma-Aldrich
Myosin, Smooth Muscle (EP166) Rabbit Monoclonal Primary Antibody