Cancer stem cells in urologic cancers

There is evolving evidence for the so-called cancer stem cell (CSC) hypothesis, which holds that intra-tumoral heterogeneity in urologic malignancies is hierarchical and that not all cells have the ability to proliferate indefinitely and to generate metastases. This has far-reaching implications for research and the clinical management of urologic malignancies. In this review, we outline the tenets and implications of the CSC hypothesis, summarize existing evidence for CSCs in urologic malignancies, suggest research directions that may better dissect intra-tumoral heterogeneity in urologic cancers, and outline novel therapeutic modalities implied by the CSC hypothesis.