Aims Cell adhesion molecule 4 (CADM4) is a novel tumour suppressor. The purpose of this study was to investigate the correlation between its expression and the expression of E-cadherin and Ki-67 in colorectal adenocarcinomas, as well as its effect on patient survival.

Methods We evaluated CADM4 expression in tissue microarrays of 513 colorectal adenocarcinomas by immunohistochemistry.

Results CADM4 was highly expressed in 210 of the 513 colorectal adenocarcinomas; expression was reduced in 185 cases and absent in the remaining cases. Loss of CADM4 expression was correlated with larger tumour size (6.2±2.1 cm vs 5.3±2.0 cm, p<0.001), mucinous tumour type (61.5% vs 20.9%, p<0.001), lymph node metastasis (31.4% vs 20.9%, p=0.022), higher Dukes stage (25.5% vs 19.6%, p=0.044), poorer differentiation (38.5% vs 18.8%, p<0.001), absence of E-cadherin expression (28.5% vs 16.0%, p=0.007) and presence of Ki-67 expression (27.3% vs 12.3%, p<0.001). In univariable Cox regression analysis, absence of CADM4 expression was associated with poorer overall survival (HR 0.712; 95% CI 0.512 to 0.989, p=0.042) and disease-free survival (HR 0.732; 95% CI 0.546 to 0.981, p=0.037). In multivariate analysis with the Cox proportional hazards model, CADM4 expression was not an independent prognostic factor of overall survival (HR 0.726; 95% CI 0.516 to 1.021, p=0.066) and disease-free survival (HR 0.762; 95% CI 0.563 to 1.033, p=0.080).

Conclusions Loss of CADM4 expression is relatively frequent in colorectal adenocarcinomas and may play an important role in cancer progression and patient survival.