WW domain-containing oxidoreductase (WWOX) is a proapoptotic protein and a tumor suppressor gene. Because mutation or deletion in the coding region of WWOX is rarely found, it is speculated that the appearance of aberrant transcripts affects progression of many cancers. In addition, protein levels of WWOX, its Tyr33-phosphorylated form, and WOX2 are significantly down-regulated in the neurons of Alzheimer's hippocampi.