Role of Stem Cells in Colorectal Cancer Progression and Prognostic and Predictive Characteristics of Stem Cell Markers in Colorectal Cancer

In the last decade, an increasing number of studies on tumor stem cell theory stating that there is only a small fraction of tumor cells capable of inducing tumor growth have been published. These cells can not only differentiate into more mature tumor cells, but also can maintain their own pool, that is the capacity for self-renewal. There are distinct subpopulations of cells within a tumor that express different combinations of stem cell markers and have different functions. The following markers are typically considered as markers of colorectal adenocarcinoma stem cells: CD133, CD144, CD24, CD166, CD44, CD29, ALDH1, LGR5, and CXCR4. However, data on the role of cancer stem cells in the process of colorectal cancer progression, their prognostic and predictive role are lacking. Researches on the phenotype, molecular and functional properties of this tumor cell subpopulation in both primary site and metastases of colorectal cancer are of great interest because they can allow developing new diagnostic and therapeutic strategies in the future.