Cancer Stem Cells
Cancer stem cells are a population of tumor cells that possess the defining features of clonogenicity and self-renewal. Cancer stem cells were first identified in leukemia using the experimental technique of xenotransplantation. Since this early discovery, cancer stem cells have now been identified in many other malignancies. Contemporary assays such as lineage tracing allow for a deeper understanding about the prevalence and behavior of these cells. In this article we discuss the advances in the field and future directions together with an emphasis on the importance of understanding cancer stem cells in the context of clonal genetic heterogeneity.