Article

Journal of Mammary Gland Biology and Neoplasia

, Volume 10, Issue 3, pp 249-260

First online:

Myoepithelial Cells: Autocrine and Paracrine Suppressors of Breast Cancer Progression

  • Sanford H. BarskyAffiliated withDepartment of Pathology, The Ohio State University College of MedicineDepartment of Pathology, The Ohio State University College of Medicine Email author 
  • , Nina J. KarlinAffiliated withDepartment of Medicine, Division of Hematology-Oncology, UCLA-Olive View Medical Center

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Abstract

Host cellular paracrine regulation of tumor progression is an important determinant of tumor biology but one cell that has been ignored in this regulation is the myoepithelial cell. Myoepithelial cells surround normal ducts and precancerous lesions, especially of the breast and form a natural border separating proliferating epithelial cells from proliferating endothelial cells (angiogenesis). Myoepithelial cells may thus negatively regulate tumor invasion and metastasis. Whereas epithelial cells are susceptible targets for transforming events, myoepithelial cells are resistant. Therefore, it can be said that myoepithelial cells function as both autocrine as well as paracrine tumor suppressors. Our laboratory has found that myoepithelial cells secrete a number of suppressor molecules including high amounts of diverse proteinase inhibitors and angiogenic inhibitors but low amounts of proteinases and angiogenic factors compared to common malignant cell lines. This observation has been made in vitro, in mice, and in humans and suggests that myoepithelial cells exert pleiotropic suppressive effects on tumor progression. The gene expression profile of myoepithelial cells may explain the pronounced anti-invasive and anti-angiogenic effects of myoepithelial cells on carcinoma cells and may also account for the reduced malignancy of myoepithelial tumors, which are devoid of appreciable angiogenesis and invasive behavior.

Key Words

myoepithelial cells tumor suppression expression profile angiogenic inhibitors proteinase inhibitors