title: Cancer stem cells, a fuzzy evolving concept: a cell population or a cell property?
abstract: The cancer stem cells (CSC) hypothesis represents a pathological extrapolation of the physiological concept of embryonic and somatic stem cells. In its initial definition, it encompassed the hypothesis of a qualitatively distinct population of immortal cancer cells originating from somatic stem cells, which generate in xenotransplants by a deterministic irreversible process, the hierarchy of more differentiated finite lifespan derived cells, which constitute, themselves, the bulk of the cancer. These CSC would express specific biomarkers and gene expressions related to chemo- and radioresistance, stemness, epithelial-mesenchymal transition, etc. No convincing congruence of several of these properties in one cell population has been demonstrated. The concept has greatly evolved with time and with different authors ("the plasticity of cancer stem cells"), leading to a minimal definition of cells generating a hierarchy of derived cells. In this article these concepts are analyzed. It is proposed that stemness is a property, more or less reversible, a hallmark of some cells at some time in a cancer cell population, as immortality, dormancy, chemo- or radioresistance, epithelial-mesenchymal transition etc. These phenotypic properties represent the result of independent, linked, or more or less congruent, genetic, epigenetic, or signaling programs.
authors.affiliation: Institute of Inrdisciplinary Research (IRIBHM); University of Brussels; Brussels, Belgium.
authors.forename: Aline
authors.initials: A
authors.lastname: Antoniou
authors.affiliation: Institute of Inrdisciplinary Research (IRIBHM); University of Brussels; Brussels, Belgium.
authors.forename: Aline
authors.initials: A
authors.lastname: Hébrant
authors.affiliation: Institute of Inrdisciplinary Research (IRIBHM); University of Brussels; Brussels, Belgium.
authors.forename: Genevieve
authors.initials: G
authors.lastname: Dom
authors.affiliation: Institute of Inrdisciplinary Research (IRIBHM); University of Brussels; Brussels, Belgium.
authors.forename: Jacques E
authors.initials: JE
authors.lastname: Dumont
authors.affiliation: Institute of Inrdisciplinary Research (IRIBHM); University of Brussels; Brussels, Belgium; Wellbio; School of Medicine; University of Brussels; Brussels, Belgium.
authors.forename: Carine
authors.initials: C
authors.lastname: Maenhaut
mesh_terms: D002454:Cell Differentiation; D058750:Epithelial-Mesenchymal Transition; D006801:Humans; D014411:Neoplastic Stem Cells / Q000166:cytology* / Q000502:physiology*; D009626:Terminology as Topic
keywords: cancer; cancer hallmarks; stem cell; stemness; tumor