Increasing evidence shows that a variety of cancers arise from the transformation of normal stem cells into cancer stem cells (CSCs). CSCs are thought to sustain cancer progression, invasion, metastasis.
Epigenetic alterations have come to prominence in biomedical research. In particular, hypermethylation of CpG islands located in the promoter regions of tumor-suppressor genes is now firmly established as an important mechanism for gene inactivation in cancer.