title: Breast cancer stem cells.
abstract: Breast cancer stem cells (BCSCs) constitute a subpopulation of tumor cells that express stem cell-associated markers and have a high capacity for tumor generation in vivo. Identification of BCSCs from tumor samples or breast cancer cell lines has been based mainly on CD44(+)/CD24(-/low) or ALDH(+) phenotypes. BCSCs isolation has allowed the analysis of the molecular mechanisms involved in their origin, self-renewal, differentiation into tumor cells, resistance to radiation therapy and chemotherapy, and invasiveness and metastatic ability. Molecular genetic analysis using knockout animals and inducible transgenics has identified NF-κB, c-Jun, p21(CIP1), and Forkhead-like-protein Dach1 involvement in BCSC expansion and fate. Clinical analyses of BCSCs in breast tumors have found a correlation between the proportion of BCSCs and poor prognosis. Therefore, new therapies that specifically target BCSCs are an urgent need. We summarize recent evidence that partially explain the biological characteristics of BCSCs.
authors.affiliation: Department of Cancer Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA. marcovelasco@unam.mx
authors.forename: Marco A
authors.initials: MA
authors.lastname: Velasco-Velázquez
authors.forename: Nora
authors.initials: N
authors.lastname: Homsi
authors.forename: Marisol
authors.initials: M
authors.lastname: De La Fuente
authors.forename: Richard G
authors.initials: RG
authors.lastname: Pestell
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000532:radiotherapy; D002454:Cell Differentiation / Q000187:drug effects / Q000528:radiation effects; D019008:Drug Resistance, Neoplasm; D006801:Humans; D009362:Neoplasm Metastasis; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000473:pathology / Q000528:radiation effects