Журнал канцерогенеза и мутагенеза

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Do Cancer Stem Cells have an Immunomodulatory Role Different from the Bulk of Tumor Cells?

Hazem Ghebeh and Monther Al-Alwan

Cancer is one of the leading causes of death worldwide. In normal settings, the immune system is responsible for clearing cancer cells from our body. However, many patients develop immune tolerance to tumor cells through upregulation of immune regulatory molecules, release of immune suppressive factors in the tumor microenvironment and/or recruitment of regulatory/suppressive cells that impede the function of other fully activated effector immune cells. In spite of significant progress that have been achieved in increasing our understanding in this field, it is unknown whether all tumor cells exert similar inhibitory effect on the immune system or only specific subset(s) of tumor cells possess this feature. There is accumulating evidence that cancer is originated and sustained by a small population of cells called “Cancer Stem Cells (CSCs)”. These cells share many characteristics of the normal stem cells including the selfrenewing ability. Thus, it is possible that they also have the immune privilege properties of normal stem cells. At least this has been shown to be the case for two types of cancers: melanoma and glioma. In this report we will review the role of CSCs in the creation of immune suppressive microenvironment which finally leads to tumor escape from the immune system surveillance.