Comment

More than 80% of colorectal tumours harbour mutations in the adenomatous polyposis coli (APC) tumour suppressor gene which encodes a 310 kDa cytoplasmic protein with several structural and binding domains.1 One of its functions is to bind and degrade β-catenin, a promiscuous cytoskeletal protein, which associates with APC, E-cadherin (a cell–cell adhesion molecule), epidermal growth factor receptor, and two nuclear transcription factors (members of the Lef/Tcf family).2-4 β-catenin and APC are bound in a multiprotein complex with two other proteins, a serine/threonine kinase enzyme GSK-3β that negatively regulates β-catenin and a newly discovered molecule, conductin (or axin), which assembles this complex.5 In normal colonic epithelial cells, β-catenin is either continuously degraded via its interaction with wild type APC or is localised at the adherens junctions as part of the E-cadherin complex. However, in colon cancer cells …