Published online Nov 26, 2014. doi: 10.4252/wjsc.v6.i5.614
Revised: September 12, 2014
Accepted: September 17, 2014
Published online: November 26, 2014
Processing time: 62 Days and 23.9 Hours
Currently, thyroid cancer is one of the most common endocrine cancer in the United States. A recent involvement of sub-population of stem cells, cancer stem cells, has been proposed in different histological types of thyroid cancer. Because of their ability of self-renewal and differentiation into various specialized cells in the body, these putative cells drive tumor genesis, metastatic activity and are responsible to provide chemo- and radioresistant nature to the cancer cells in the thyroid gland. Our Review was conducted from previously published literature to provide latest apprises to investigate the role of embryonic, somatic and cancer stem cells, and discusses the hypothesis of epithelial-mesenchymal transition. Different methods for their identification and isolation through stemness markers using various in vivo and in vitro methods such as flow cytometry, thyrosphere formation assay, aldehyde dehydrogenase activity and ATP-binding cassette sub-family G member 2 efflux-pump mediated Hoechst 33342 dye exclusion have been discussed. The review also outlines various setbacks that still remain to target these tumor initiating cells. Future perspectives of therapeutic strategies and their potential to treat advanced stages of thyroid cancer are also disclosed in this review.
Core tip: The concept of cancer stem cells in thyroid gland tumors has recently evolved. Since this sub-population of cells appear to have a potential for self-renewal and cell differentiation, their role envisions newer ideas in the field of anti-cancer therapy and regenerative medicine. The controversies have been raised for their origin in different cell lines and effectiveness in thyroid pathologies including chemo- and radio-resistant thyroid cancer. Newer concepts like epithelial-mesenchymal transition have been investigated to define its role in metastatic activity. Literature discusses various methods to target these cells by interfering signaling pathways, destruction of niche and other factors which facilitate and sustain tumor growth.