Regulation and role of Par-4 in gastrointestinal tumors

Cancers of the gastrointestinal (GI) tract are the second leading cause of cancer deaths worldwide for both sexes. These include esophageal cancers, gastric cancers, cholangiocarcinomas, cancers of the small bowel, and colorectal cancer. Of these, colorectal cancers account for almost half of the cancers of the GI tract. In a number of these cancers, Par-4 has been shown to play a negative role in the progression of cancer. Higher Par-4 activity has been shown to indicate a better prognosis, as, when activated, it causes apoptosis in the cancer cells, both locally and distally. However, many factors affect both the expression and the activity of Par-4 in GI cancer cells. This chapter details what is known about the role and regulation of Par-4 in tumors of the GI tract.