title: Myoepithelial cells: autocrine and paracrine suppressors of breast cancer progression.
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.
authors.affiliation: Department of Pathology, The Ohio State University College of Medicine, Columbus, Ohio 43210, USA. sanford.barsky@osumc.edu
authors.forename: Sanford H
authors.initials: SH
authors.lastname: Barsky
authors.forename: Nina J
authors.initials: NJ
authors.lastname: Karlin
mesh_terms: D020533:Angiogenesis Inhibitors / Q000378:metabolism; D000818:Animals; D018931:Antineoplastic Agents, Hormonal / Q000378:metabolism; D019898:Autocrine Communication; D001940:Breast / Q000378:metabolism / Q000473:pathology; D001943:Breast Neoplasms / Q000473:pathology* / Q000503:physiopathology*; D018270:Carcinoma, Ductal, Breast / Q000473:pathology* / Q000503:physiopathology* / Q000556:secondary; D018450:Disease Progression; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism* / Q000473:pathology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology; D016147:Genes, Tumor Suppressor / Q000502:physiology; D006801:Humans; D008297:Male; D051379:Mice; D009361:Neoplasm Invasiveness / Q000503:physiopathology; D009389:Neovascularization, Pathologic; D019899:Paracrine Communication; D011230:Precancerous Conditions / Q000473:pathology
chemical_list: D020533:Angiogenesis Inhibitors; D018931:Antineoplastic Agents, Hormonal