The role of cancer stem cells in relapse of solid tumors.
Front Biosci (Elite Ed). 2012 ;4:1528-41. Epub 2012 Jan 1. PMID: 22201973
Department of Medical Microbiology, Immunology and Cell Biology and Simmons Cancer Institute, Southern Illinois University School of Medicine, Springfield, IL 62794, USA.
Recurrence at secondary locations, often years after removal of the primary tumor, accounts for most of the mortality associated with solid tumors. Metastasis, resistance to chemo- and radiotherapy, and eventual relapse have been attributed to a distinct tumor subpopulation known as cancer stem cells (CSCs). In this review, we consider the properties of CSCs that lead to these outcomes, in particular the relation between epithelial-to-mesenchymal transition, stemness, and tumor initiation. We compare recent clinical and laboratory studies of breast cancer, glioblastoma, and melanoma that illustrate how most current anticancer regimens select for cells with mesenchymal and CSC properties and therefore sow the seeds of relapse. Finally, we discuss the emerging paradigm of combined therapy that targets both CSC and non-CSC tumor components.