Introduction: The Role of Myoepithelial Cells in Integration of Form and Function in the Mammary Gland

Abstract

The importance of the microenvironment and context in regulation of tissueand organ-specific functions, as well as in progression to malignancy, is beginning to be recognized by the larger scientific community. It is true that no cell is an island, and this fact has been clearly demonstrated for the mammary gland, an organ that has provided much of the pioneering work in this area and lends itself to detailed analysis of the molecular mechanisms involved. This issue of Journal of Mammary Gland Biology and Neoplasia was conceived to bring more balance to the research on the breast and breast diseases. For decades, there has been an overwhelming emphasis on the luminal epithelial/secretory cells of the mammary gland, but the myoepithelial cell has largely been ignored. Even when believed to be important, its significance has been explored only in lactation, where it facilitates milk secretion via oxytocin-induced contraction. Only recently has a serious study of the myoepithelial cell as a legitimate contributor to normal function and breast cancer begun. The invited chapters in this issue show that until we begin to see the breast as the integrated organ that it is, we will not be able to understand either breast cancer or normal breast function. This integration is not just among the different cell types of the