Abstract

AIMS: To investigate alpha catenin expression in surgically resected human colorectal cancers to evaluate its prognostic value during long term follow up. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.