Figure 2.

Proof of concept for epigenetic cancer. Non-neoplastic cells in the kidney can be reprogrammed into iPSCs in teratoma in vivo. However, incomplete reprogramming caused by transient expression of reprogramming factors results in the development of a cancer resembling Wilms’ tumor, a common pediatric kidney cancer. The tumor cells are easily fully reprogrammed into iPSCs by additional expression of reprogramming factors in vitro. The kidney tumor-derived iPSCs differentiate into non-neoplastic kidney cells in chimeric mice, proving that kidney cancer cells in this model have not undergone irreversible genetic transformation. This result suggests that particular types of cancer can develop mainly through disruption of epigenetic regulation. Abbreviation: iPSC, induced pluripotent stem cell.