Expression of sFRP-4 and β-catenin in human colorectal carcinoma

Alterations to the Wnt signalling pathway occur in the majority of colorectal cancers and result in abnormal accumulation of β-catenin. The secreted frizzled related proteins (sFRPs) are antagonists that bind Wnt and inhibit signalling along this pathway. We investigated expression of the sFRP family member, sFRP-4, and β-catenin in 1044 human colorectal carcinomas using tissue microarrays and immunohistochemistry. Both proteins showed markedly increased expression levels in tumors compared to normal mucosa, but no significant associations with pathological features or with patient outcome. sFRP-4 was co-expressed with β-catenin, p53, and COX-2, while the absence of β-catenin expression was strongly associated with loss of expression of the MLH1 mismatch repair gene. In contrast to other sFRP family members, sFRP-4 expression appears to be upregulated in colorectal carcinoma.