Defects in the regulation of β-catenin in colorectal cancer

The molecular events that contribute to the progression of colon cancer are beginning to unravel. An initiating and probably obligatory event is the oncogenic activation of β-catenin. This can come about by the loss of its negative regulator the adenomatous polyposis coli (APC) protein, or by mutations in the β-catenin gene that result in a more stable protein product. The interaction between APC and β-catenin, and additional proteins that affect assembly and signaling along this pathway, are discussed.