Prostate Tissue Stem Cells and Prostate Cancer Progression

Tumor heterogeneity has been ascribed to the presence of cells with stem cell characteristics in a variety of malignancies, and prostate cancer (PCa) is no exception. Phenotypically distinct subsets of tumor cells that are functionally unique in tumor-regenerating potential, termed cancer stem cells (CSCs), have been identified in both mouse and human prostate cancer. Whether, or not, CSCs arise from normal tissue stem cells is an important philosophical question with potential clinical implications. Regardless of the origin of the tumor-initiating cell, prostatic CSCs share certain attributes with normal prostate stem cells, including self-renewal, multi-lineage potential, and castration-resistance. In this chapter, cellular hierarchies in both normal prostate and prostate tumors are reviewed, and the cell-of-origin from which prostate tumors may arise is further considered.