Reduced expression of alpha catenin is associated with poor prognosis in colorectal carcinoma.

To investigate alpha catenin expression in surgically resected human colorectal cancers to evaluate its prognostic value during long term follow up. Immunohistochemistry was used to compare the expression of alpha catenin with conventional prognostic factors in 187 colorectal cancer patients treated in Kuopio University Hospital and followed up for a mean of 14 years. The hypothesis that the intensity of expression of alpha catenin and its distribution in cancer cells is correlated with survival was tested with the long-rank test, hazard ratios, and their confidence intervals. Uniform membranous alpha catenin staining localised to the intercellular borders was observed in 46% of the tumours; 55% of all tumours had either heterogeneous or negative alpha catenin expression, and staining intensity was either negative or weak in 42% of the tumours. The cancer related and recurrence-free survival rates were lower among patients with a weak alpha catenin intensity in tumour epithelium (p < 0.001), a low fraction of positive tumour cells (p < 0.001), and an additional cytoplasmic accumulation of alpha catenin (p < 0.001). In multivariate analysis, the intensity of alpha catenin expression in tumour epithelium predicted cancer related survival independently; alpha catenin localisation in tumour epithelium was an independent prognostic factor of recurrence-free survival in the group as a whole and in the T1-3N0M0 tumour subgroup. A low proportion of positive carcinoma cells, additional cytoplasmic accumulation of alpha catenin, and reduced expression intensity in tumour epithelium predict a poor survival rate. The results suggest that alpha catenin has prognostic significance in colorectal cancer.