Aims: To investigate dysregulation of the wnt signalling pathway by assessing beta-catenin expression/increasing expression and loss of cytoplasmic adenomatous polyposis coli (APC) and membranous E-cadherin in colorectal cancer (CRC) and determining the prognostic significance of these variables.
Methods and results: Unselected, non-consecutive CRC resections (n = 1420) were subdivided into three groups: mismatch repair (MMR)-proficient, MLH1- and presumed hereditary non-polyposis colonic cancer (HNPCC). Immunohistochemical analysis of beta-catenin expression (0% versus > 0%) and increasing expression (increasing percentage-positivity) and loss of APC and E-cadherin was performed using the tissue microarray technique. In MMR-proficient CRC, increased nuclear beta-catenin expression and loss of membranous E-cadherin were independently associated with higher N stage (P = 0.03 and < 0.0001), vascular invasion (P < 0.01 and < 0.001) and worse survival (P < 0.01 and < 0.001). Additionally, there was an association between loss of membranous E-cadherin and higher T stage (P = 0.03). In MLH1- CRC, loss of membranous E-cadherin was associated with higher N stage (P = 0.05) and worse survival (P = 0.03). In presumed HNPCC CRC nuclear beta-catenin and membranous E-cadherin were not associated with tumour progression or worse survival. In all CRC subsets loss of cytoplasmic APC was not associated with clinicopathological features.
Conclusions: Increasing nuclear beta-catenin expression and loss of membranous E-cadherin are independent, adverse prognostic factors in MMR-proficient and MLH1- CRC.