Copyright © 2009 Zhuo (Georgia) Chen. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Linked References

1. D. M. Parkin, F. Bray, J. Ferlay, and P. Pisani, “Global cancer statistics, 2002,” CA: A Cancer Journal for Clinicians, vol. 55, no. 2, pp. 74–108, 2005. View at Scopus
2. D. M. Parkin, P. Pisani, and J. Ferlay, “Global cancer statistics,” CA: A Cancer Journal for Clinicians, vol. 49, no. 1, pp. 33–64, 1999.
3. A. Jemal, T. Murray, and E. Ward, “Cancer statistics, 2005,” CA: A Cancer Journal for Clinicians, vol. 55, no. 1, pp. 10–30, 2005.
4. R. I. Haddad and D. M. Shin, “Recent advances in head and neck cancer,” The New England Journal of Medicine, vol. 359, no. 11, pp. 1143–1154, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
5. S. J. Jang, I. Chiba, A. Hirai, W. K. Hong, and L. Mao, “Multiple oral squamous epithelial lesions: are they genetically related?” Oncogene, vol. 20, no. 18, pp. 2235–2242, 2001. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
6. X. Wang, M. Fan, X. Chen, et al., “Intratumor genomic heterogeneity correlates with histological grade of advanced oral squamous cell carcinoma,” Oral Oncology, vol. 42, no. 7, pp. 740–744, 2006. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
7. A. K. El-Naggar, K. Hurr, M. A. Luna, et al., “Intratumoral genetic heterogeneity in primary head and neck squamous carcinoma using microsatellite markers,” Diagnostic Molecular Pathology, vol. 6, no. 6, pp. 305–308, 1997. View at Publisher · View at Google Scholar · View at Scopus
8. C. Jin, Y. Jin, J. Wennerberg, et al., “Karyotypic heterogeneity and clonal evolution in squamous cell carcinomas of the head and neck,” Cancer Genetics and Cytogenetics, vol. 132, no. 2, pp. 85–96, 2002. View at Publisher · View at Google Scholar · View at Scopus
9. H.-R. Choi, E. M. Sturgis, D. I. Rosenthal, et al., “Sarcomatoid carcinoma of the head and neck: molecular evidence for evolution and progression from conventional squamous cell carcinomas,” American Journal of Surgical Pathology, vol. 27, no. 9, pp. 1216–1220, 2003. View at Publisher · View at Google Scholar · View at Scopus
10. I. J. Fidler and M. L. Kripke, “Metastasis results from preexisting variant cells within a malignant tumor,” Science, vol. 197, no. 4306, pp. 893–895, 1977. View at Scopus
11. G. Heppner, K. Yamashina, B. Miller, and F. Miller, “Tumor heterogeneity in metastasis,” Progress in Clinical and Biological Research, vol. 212, pp. 45–59, 1986. View at Scopus
12. M. F. Clarke, J. E. Dick, P. B. Dirks, et al., “Cancer stem cells—perspectives on current status and future directions: AACR workshop on cancer stem cells,” Cancer Research, vol. 66, no. 19, pp. 9339–9344, 2006. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
13. T. Reya, S. J. Morrison, M. F. Clarke, and I. L. Weissman, “Stem cells, cancer, and cancer stem cells,” Nature, vol. 414, no. 6859, pp. 105–111, 2001. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
14. D. M. Owens and F. M. Watt, “Contribution of stem cells and differentiated cells to epidermal tumours,” Nature Reviews Cancer, vol. 3, no. 6, pp. 444–451, 2003. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
15. B. J. P. Huntly and D. G. Gilliland, “Cancer biology: summing up cancer stem cells,” Nature, vol. 435, no. 7046, pp. 1169–1170, 2005. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
16. P. Dalerba, R. W. Cho, and M. F. Clarke, “Cancer stem cells: models and concepts,” Annual Review of Medicine, vol. 58, pp. 267–284, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
17. J. E. Visvader and G. J. Lindeman, “Cancer stem cells in solid tumours: accumulating evidence and unresolved questions,” Nature Reviews Cancer, vol. 8, no. 10, pp. 755–768, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
18. M. Al-Hajj, M. S. Wicha, A. Benito-Hernandez, S. J. Morrison, and M. F. Clarke, “Prospective identification of tumorigenic breast cancer cells,” Proceedings of the National Academy of Sciences of the United States of America, vol. 100, no. 7, pp. 3983–3988, 2003. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
19. A. Eramo, F. Lotti, G. Sette, et al., “Identification and expansion of the tumorigenic lung cancer stem cell population,” Cell Death and Differentiation, vol. 15, no. 3, pp. 504–514, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
20. C. J. Lee, C. Li, and D. M. Simeone, “Human pancreatic cancer stem cells: implications for how we treat pancreatic cancer,” Translational Oncology, vol. 1, no. 1, pp. 14–18, 2008.
21. S. K. Singh, C. Hawkins, I. D. Clarke, et al., “Identification of human brain tumour initiating cells,” Nature, vol. 432, no. 7015, pp. 396–401, 2004. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
22. A. T. Collins, P. A. Berry, C. Hyde, M. J. Stower, and N. J. Maitland, “Prospective identification of tumorigenic prostate cancer stem cells,” Cancer Research, vol. 65, no. 23, pp. 10946–10951, 2005. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
23. C. F. Bender Kim, E. L. Jackson, A. E. Woolfenden, et al., “Identification of bronchioalveolar stem cells in normal lung and lung cancer,” Cell, vol. 121, no. 6, pp. 823–835, 2005. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
24. D. Fang, T. K. Nguyen, K. Leishear, et al., “A tumorigenic subpopulation with stem cell properties in melanomas,” Cancer Research, vol. 65, no. 20, pp. 9328–9337, 2005. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
25. L. Xin, D. A. Lawson, and O. N. Witte, “The Sca-1 cell surface marker enriches for a prostate-regenerating cell subpopulation that can initiate prostate tumorigenesis,” Proceedings of the National Academy of Sciences of the United States of America, vol. 102, no. 19, pp. 6942–6947, 2005. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
26. L. Patrawala, T. Calhoun, R. Schneider-Broussard, et al., “Highly purified CD${44}^{+}$ prostate cancer cells from xenograft human tumors are enriched in tumorigenic and metastatic progenitor cells,” Oncogene, vol. 25, no. 12, pp. 1696–1708, 2006. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
27. C. Li, D. G. Heidt, P. Dalerba, et al., “Identification of pancreatic cancer stem cells,” Cancer Research, vol. 67, no. 3, pp. 1030–1037, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
28. L. Ricci-Vitiani, A. Pagliuca, E. Palio, A. Zeuner, and R. De Maria, “Colon cancer stem cells,” Gut, vol. 57, no. 4, pp. 538–548, 2008.
29. Z. F. Yang, D. W. Ho, M. N. Ng, et al., “Significance of CD${90}^{+}$ cancer stem cells in human liver cancer,” Cancer Cell, vol. 13, no. 2, pp. 153–166, 2008.
30. T. Schatton, G. F. Murphy, N. Y. Frank, et al., “Identification of cells initiating human melanomas,” Nature, vol. 451, no. 7176, pp. 345–349, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
31. P. Dalerba, S. J. Dylla, I.-K. Park, et al., “Phenotypic characterization of human colorectal cancer stem cells,” Proceedings of the National Academy of Sciences of the United States of America, vol. 104, no. 24, pp. 10158–10163, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
32. P. C. Hermann, S. L. Huber, T. Herrler, et al., “Distinct populations of cancer stem cells determine tumor growth and metastatic activity in human pancreatic cancer,” Cell Stem Cell, vol. 1, no. 3, pp. 313–323, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
33. L. Patrawala, T. Calhoun, R. Schneider-Broussard, et al., “Side population is enriched in tumorigenic, stem-like cancer cells, whereas ${\text{ABCG2}}^{+}$ and ${\text{ABCG2}}^{-}$ cancer cells are similarly tumorigenic,” Cancer Research, vol. 65, no. 14, pp. 6207–6219, 2005. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
34. E. Charafe-Jauffret, F. Monville, C. Ginestier, et al., “Cancer stem cells in breast: current opinion and future challenges,” Pathobiology, vol. 75, no. 2, pp. 75–84, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
35. L. L. Campbell and K. Polyak, “Breast tumor heterogeneity: cancer stem cells or clonal evolution?” Cell Cycle, vol. 6, no. 19, pp. 2332–2338, 2007. View at Scopus
36. M. S. Wicha, “Cancer stem cell heterogeneity in hereditary breast cancer,” Breast Cancer Research, vol. 10, no. 2, p. 105, 2008. View at Scopus
37. M. Shipitsin, L. L. Campbell, P. Argani, et al., “Molecular definition of breast tumor heterogeneity,” Cancer Cell, vol. 11, no. 3, pp. 259–273, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
38. M. Al-Hajj, M. S. Wicha, A. Benito-Hernandez, S. J. Morrison, and M. F. Clarke, “Prospective identification of tumorigenic breast cancer cells,” Proceedings of the National Academy of Sciences of the United States of America, vol. 100, no. 7, pp. 3983–3988, 2003. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
39. S. Bao, Q. Wu, R. E. McLendon, et al., “Glioma stem cells promote radioresistance by preferential activation of the DNA damage response,” Nature, vol. 444, no. 7120, pp. 756–760, 2006. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
40. C. A. O'Brien, A. Pollett, S. Gallinger, and J. E. Dick, “A human colon cancer cell capable of initiating tumour growth in immunodeficient mice,” Nature, vol. 445, no. 7123, pp. 106–110, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
41. L. Ricci-Vitiani, D. G. Lombardi, E. Pilozzi, et al., “Identification and expansion of human colon-cancer-initiating cells,” Nature, vol. 445, no. 7123, pp. 111–115, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
42. M. A. Goodell, K. Brose, G. Paradis, A. S. Conner, and R. C. Mulligan, “Isolation and functional properties of murine hematopoietic stem cells that are replicating in vivo,” Journal of Experimental Medicine, vol. 183, no. 4, pp. 1797–1806, 1996. View at Publisher · View at Google Scholar · View at Scopus
43. D. G. Tang, L. Patrawala, T. Calhoun, et al., “Prostate cancer stem/progenitor cells: identification, characterization, and implications,” Molecular Carcinogenesis, vol. 46, no. 1, pp. 1–14, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
44. P. Dell'Albani, “Stem cell markers in gliomas,” Neurochemical Research, vol. 33, no. 12, pp. 2407–2415, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
45. M. Dean, T. Fojo, and S. Bates, “Tumour stem cells and drug resistance,” Nature Reviews Cancer, vol. 5, no. 4, pp. 275–284, 2005. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
46. N. A. Dallas, L. Xia, F. Fan, et al., “Chemoresistant colorectal cancer cells, the cancer stem cell phenotype, and increased sensitivity to insulin-like growth factor-I receptor inhibition,” Cancer Research, vol. 69, no. 5, pp. 1951–1957, 2009. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
47. C. Hirschmann-Jax, A. E. Foster, G. G. Wulf, et al., “A distinct “side population” of cells with high drug efflux capacity in human tumor cells,” Proceedings of the National Academy of Sciences of the United States of America, vol. 101, no. 39, pp. 14228–14233, 2004. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
48. A. R. Tan, G. Alexe, and M. Reiss, “Transforming growth factor-$\beta$ signaling: emerging stem cell target in metastatic breast cancer?” Breast Cancer Research and Treatment, vol. 115, no. 3, pp. 453–495, 2008.
49. D. C. Radisky and M. A. LaBarge, “Epithelial-mesenchymal transition and the stem cell phenotype,” Cell Stem Cell, vol. 2, no. 6, pp. 511–512, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
50. T. Brabletz, A. Jung, S. Spaderna, F. Hlubek, and T. Kirchner, “Opinion: migrating cancer stem cells—an integrated concept of malignant tumour progression,” Nature Reviews Cancer, vol. 5, no. 9, pp. 744–749, 2005. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
51. T. Brabletz, F. Hlubek, S. Spaderna, et al., “Invasion and metastasis in colorectal cancer: epithelial-mesenchymal transition, mesenchymal-epithelial transition, stem cells and $\beta$-catenin,” Cells Tissues Organs, vol. 179, no. 1-2, pp. 56–65, 2005. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
52. S. A. Mani, W. Guo, M.-J. Liao, et al., “The epithelial-mesenchymal transition generates cells with properties of stem cells,” Cell, vol. 133, no. 4, pp. 704–715, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
53. P. C. Hermann, S. L. Huber, and C. Heeschen, “Metastatic cancer stem cells: a new target for anti-cancer therapy?” Cell Cycle, vol. 7, no. 2, pp. 188–193, 2008. View at Scopus
54. L. Patrawala, T. Calhoun-Davis, R. Schneider-Broussard, and D. G. Tang, “Hierarchical organization of prostate cancer cells in xenograft tumors: the CD${44}^{+}$$\alpha$2$\beta$$1^{+}$ cell population is enriched in tumor-initiating cells,” Cancer Research, vol. 67, no. 14, pp. 6796–6805, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
55. C. Odoux, H. Fohrer, T. Hoppo, et al., “A stochastic model for cancer stem cell origin in metastatic colon cancer,” Cancer Research, vol. 68, no. 17, pp. 6932–6941, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
56. M. E. P. Prince and L. E. Ailles, “Cancer stem cells in head and neck squamous cell cancer,” Journal of Clinical Oncology, vol. 26, no. 17, pp. 2871–2875, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
57. M. E. Prince, R. Sivanandan, A. Kaczorowski, et al., “Identification of a subpopulation of cells with cancer stem cell properties in head and neck squamous cell carcinoma,” Proceedings of the National Academy of Sciences of the United States of America, vol. 104, no. 3, pp. 973–978, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
58. A. Okamoto, K. Chikamatsu, K. Sakakura, et al., “Expansion and characterization of cancer stem-like cells in squamous cell carcinoma of the head and neck,” Oral Oncology, vol. 45, no. 7, pp. 633–639, 2009. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
59. P. Zhang, Y. Zhang, L. Mao, Z. Zhang, and W. Chen, “Side population in oral squamous cell carcinoma possesses tumor stem cell phenotypes,” Cancer Letters, vol. 277, no. 2, pp. 227–234, 2009. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
60. S.-H. Chiou, C.-C. Yu, C.-Y. Huang, et al., “Positive correlations of Oct-4 and Nanog in oral cancer stem-like cells and high-grade oral squamous cell carcinoma,” Clinical Cancer Research, vol. 14, no. 13, pp. 4085–4095, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
61. X. D. Wei, L. Zhou, L. Cheng, et al., “In vivo investigation of CD133 as a putative marker of cancer stem cells in hep-2 cell line,” Head and Neck, vol. 31, no. 1, pp. 94–101, 2009. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
62. S. J. Miller, R. M. Lavker, and T.-T. Sun, “Interpreting epithelial cancer biology in the context of stem cells: tumor properties and therapeutic implications,” Biochimica et Biophysica Acta, vol. 1756, no. 1, pp. 25–52, 2005. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
63. M. J. Bissell and M. A. Labarge, “Context, tissue plasticity, and cancer: are tumor stem cells also regulated by the microenvironment?” Cancer Cell, vol. 7, no. 1, pp. 17–23, 2005. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
64. D. M. Owens and F. M. Watt, “Contribution of stem cells and differentiated cells to epidermal tumours,” Nature Reviews Cancer, vol. 3, no. 6, pp. 444–451, 2003. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
65. X. Zhang, Y. Liu, M. Z. Gilcrease, et al., “A lymph node metastatic mouse model reveals alterations of metastasis-related gene expression in metastatic human oral carcinoma sublines selected from a poorly metastatic parental cell line,” Cancer, vol. 95, no. 8, pp. 1663–1672, 2002. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
66. Y. Yoon, Z. Liang, X. Zhang, et al., “CXC chemokine receptor-4 antagonist blocks both growth of primary tumor and metastasis of head and neck cancer in xenograft mouse models,” Cancer Research, vol. 67, no. 15, pp. 7518–7524, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
67. X. Zhang, L. Su, A. A. Pirani, et al., “Understanding metastatic SCCHN cells from unique genotypes to phenotypes with the aid of an animal model and DNA microarray analysis,” Clinical and Experimental Metastasis, vol. 23, no. 3-4, pp. 209–222, 2006. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
68. S. M. Janes and F. M. Watt, “New roles for integrins in squamous-cell carcinoma,” Nature Reviews Cancer, vol. 6, no. 3, pp. 175–183, 2006. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
69. S. C. Kirkland and H. Ying, “$\alpha$2$\beta$1 integrin regulates lineage commitment in multipotent human colorectal cancer cells,” Journal of Biological Chemistry, vol. 283, no. 41, pp. 27612–27619, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
70. B. Mack and O. Gires, “CD44s and CD44v6 expression in head and neck epithelia,” PLoS ONE, vol. 3, no. 10, article e3360, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
71. C. Ginestier, M. H. Hur, E. Charafe-Jauffret, et al., “ALDH1 is a marker of normal and malignant human mammary stem cells and a predictor of poor clinical outcome,” Cell Stem Cell, vol. 1, no. 5, pp. 555–567, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
72. C. Visus, D. Ito, A. Amoscato, et al., “Identification of human aldehyde dehydrogenase 1 family member a1 as a novel CD8+ T-cell-defined tumor antigen in squamous cell carcinoma of the head and neck,” Cancer Research, vol. 67, no. 21, pp. 10538–10545, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
73. M. E. Davis, Z. Chen, and D. M. Shin, “Nanoparticle therapeutics: an emerging treatment modality for cancer,” Nature Reviews Drug Discovery, vol. 7, no. 9, pp. 771–782, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus