Role of Mammary Epithelial Stem Cells in the Transition from Normal to Malignant Epithelium

摘要

A steadily growing body of evidence indicates that mouse and human mammary cancers present as clonal diseases that depend upon genetic alterations both for their initiation and progression. It is considered likely, but not proven, that the only cells of any tissue able to pass on genetic aberrations to their progeny are those that retain the capacity for cell division and that do not become terminally differentiated. This hypothesis has renewed interest in the biology and characteristics of stem cells in many tissues, with the notion that such information will be useful for the prevention, detection and therapy of the disease. In recent years it has been shown that even tissues like brain, heart, and skeletal muscle, that were previously thought to have no stem cell compartment do, in fact, have a population of stem cells. Research on the nature and characteristics of hematopoietic stem cells has produced stem cell markers and a large body of information on mechanisms of oncogenesis in myelocytes and lymphocytes. These advances have made it apparent that we need a thorough knowledge of normal growth and development and thus of the stem cell population of the mammary epithelium to understand and treat breast cancer. If the stem cell compartment plays an important role in the transition of mammary epithelium from a normal to a malignant cell population, determining the dynamics, regulation, and biology of these cells could be of considerable value to the prevention and therapy of cancer.