Sumoylation is oftentimes deregulated in cancer, and the sumoylation of C/EBPα decreases the tumor suppressive activity [10, 12], which is associated with various human cancers [3, 13, 14], suggesting that loss of C/EBPα might be associated with the switch from a cell differentiation to a cell proliferation program in cancer [15], but the mechanism of the down-regulation of C/EBPα in cancer remains elusive. This evidence concerns the gene CEBPA and neoplasm.