It was shown that CD133 + normal stem cells at the base of the adult intestinal crypts not only generate the entire intestinal epithelium, but give rise to all the neoplastic cells in mice colon tumors. The proportion of CD133 + cells in colon cancer metastases is higher than in Empagliflozin primary tumors, which reflect the well-known fact that metastatic lesions are more resistant to treatment. However, another study has shown that only a knockdown of CD44, but not CD133, strongly prevented clonal formation and inhibited tumorigenicity in the mice xenograft model, and that CD44 + is not colocalized with CD133 + cells within colorectal cancer. Similar results reported by Horst and colleagues showed that the expression of CD133 correlates with that of CD166, while both do not correlate with CD44. However, this data contradicts multiple reports which not only show colocalization of the CD133 and CD44 in several types of human cancer, but also suggest their combined expression as the best CIC marker. Such inconsistency may be due to the high heterogeneity of clinical specimens, the comparison of the data obtained on clinical specimens with data obtained on established cell lines, the diversity of experimental approaches, and the lack of highly specific CIC markers. A recent study has demonstrated that, in contrast to the established cancer cell lines, CD133 + cells in primary colorectal cancer samples showed a unique genomic aberration profile, which additionally SMI-4a highlights the point that the use of established cancer cell line is questionable. In conclusion, our data indicate that the CR4 cells isolated from liver metastasis of colon cancer patient represent an established cell line, which possesses classical features of CICs, including high tumor-initiating, clonogenic and sphere-forming capacities and exceptional resistance to anti-cancer drugs. All of the above demonstrates that these cells are a highly valuable tool for CIC research and anti-cancer drug development. About 7.6 million cancer deaths were estimated in 2008 worldwide, out of which 0.64 million people died from cancer in India. Oral cancer has emerged as one of the top three causes of cancer-related deaths in South Asian countries like India, Bangladesh, and Sri Lanka.