Cancer Stem Cell: From Conjecture to Reality

This chapter compiles various approaches of the currently advocated theory in development of most cancers through activation of the small sub-population of malignant cells with stemness characteristics, termed as cancer stem cells (CSCs). It briefly deliberates for some fundamental molecular mechanisms involved in tumorigenesis, and the potential impact of intrinsic or extrinsic factors on inducing epigenetic and/or genetic changes to improve the capacity of CSC development. Capability of CSCs to proliferate, invade, migrate, relapse and resist to several therapies has confronted cancer treatment with several obstacles. Proliferative feature of this cell type could symmetrically lead to self-renewal. Asymmetric proliferation of CSCs contributes hierarchically to not only self-renewal, but also the other types of cell, including malignant progenitor or mature cells; the procedure culminating potentially to heterogeneity of tumor bulk. In this chapter, some direct/indirect effects of microenvironmental factors and metabolism on preservation of CSC fate, invasion or even metastasis of these cells are demonstrated. Considering the molecular mechanisms promoting CSCs development, some potential therapeutic approaches are herein reviewed. Ultimately, current challenges on determination and treatment of CSCs are discussed.