PDX-1 (pancreatic/duodenal homeobox-1 protein 1).

The homeodomain-containing transcription factor pancreatic duodenal homeobox 1 (PDX-1) plays a key role in pancreatic development and β-cell function. It is a major regulator of transcription in pancreatic cells, and transactivates the insulin gene by binding to a specific DNA motif in its promoter region. Glucose also regulates insulin gene transcription through PDX-1. It has been shown that PDX-1 is required for maintaining pancreatic islet functions by activating gene expression and has a dual role in pancreatic development. It initially contributes to pancreatic formation during embryogenesis and subsequently regulates the pancreatic islet cell physiology in mature islet cells. Because of this key role in the embryologic development of the pancreas, PDX-1 expression has been investigated in pancreatic cancer cell lines and human tumors. Moreover, a few reports have described expression of PDX-1 in other human neoplasms and have investigated its potential role in differential diagnosis, but data on normal human tissues are lacking. Understanding the molecular mechanisms of pancreas formation, and especially the function of PDX-1, may contribute to the improved treatment and prevention of debilitating diseases such as diabetes, insulinomas and pancreatic carcinomas. Nevertheless, further studies are needed concerning its possible application in routine practice.