ABOUT THE COVER
During the process of tumorigenesis, differentiated cells progressively acquire changes to their gene expression program that drive the cell toward a malignant, stem cell-like state. The precise mechanisms underlying these changes are poorly defined, though it can generally be said that de-differentiation primarily occurs through the loss or inactivation of cell lineage factors. In this issue, Lee and colleagues detail new insights into the molecular mechanisms regulating the differentiation states of colorectal cancer cells. They further suggest possible avenues to reprogram tumor cells into a nonmalignant post-mitotic state by overcoming the epigenetic barrier to the differentiated state, as depicted conceptually on the cover. For more information, see the Highlight on page 1 and the article on page 118.