Tumor heterogeneity and cancer stem cell paradigm: Updates in concept, controversies and clinical relevance. Issue 9 (4th March 2014)

• Record Type: Journal Article
• Authors: Singh, Anup Kumar; Arya, Rakesh Kumar; Maheshwari, Shrankhla; Singh, Akhilesh; Meena, Sanjeev; Pandey, Priyanka; Dormond, Olivier; Datta, Dipak
• Is Part Of: International journal of cancer. Volume 136:Issue 9(2015:May 01)
• Page Start: 1991
• Page End: 2000
• Publication Date: 2014-03-04
• Subjects: Cancer -- Periodicals; Cancer -- Prevention -- Periodicals; 616.994
• DOI: 10.1002/ijc.28804
• Languages: English
• ISSNs: 0020-7136

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Although tumor heterogeneity is widely accepted, the existence of cancer stem cells (CSCs) and their proposed role in tumor maintenance has always been challenged and remains a matter of debate. Recently, a path‐breaking chapter was added to this saga when three independent groups reported the <italic>in vivo</italic> existence of CSCs in brain, skin and intestinal tumors using lineage‐tracing and thus strengthens the CSC concept; even though certain fundamental caveats are always associated with lineage‐tracing approach. In principle, the CSC hypothesis proposes that similar to normal stem cells, CSCs maintain self renewal and multilineage differentiation property and are found at the central echelon of cellular hierarchy present within tumors. However, these cells differ from their normal counterpart by maintaining their malignant potential, alteration of genomic integrity, epigenetic identity and the expression of specific surface protein profiles. As CSCs are highly resistant to chemotherapeutics, they are thought to be a crucial factor involved in tumor relapse and superficially appear as the ultimate therapeutic target. However, even that is not the end; further complication is attributed by reports of bidirectional regeneration mechanism for CSCs, one from their self‐renewal capability and another from the recently proposed concept of dynamic equilibrium between CSCs and non‐CSCs <italic>via</italic> their interconversion. This phenomenon has currently added a new layer of complexity in understanding the biology of tumor heterogeneity. In‐spite of its associated controversies, this area has rapidly emerged as the center of attention for researchers and clinicians, because of the conceptual framework it provides towards devising new therapies.</p> </abstract>