DNA Methylation, Stem Cells and Cancer

In the past few years ‘cancer stem cells’ (CSCs) area has become an interesting field of cancer research. In 19th century, Durante and Conheim [6] and after one hundred year Sell and Pierce [6, 7] issued the hypothesis that stem cells could induce cancer in all type of tissues. Unlike normal tissue stem cells, cancer stem cells are characterized by an abnormal differen‐ tiation rate, which can lead to tumor [8, 9].