Expression of Osteopontin, ZO-1 and E-cadherin in Adenoma and Adenocarcinoma of the Colon

ABSTRACT

Background: The expressions of osteopontin (OPN), zonula occludens-1 (ZO-1) and E-cadherin, known as cell adhesion-associated substances, were examined in adenoma and adenocarcinoma of the colon. The relationship of their expressions with clinicopathologic factors was examined to investigate the roles of these proteins in the development, invasion or metas- tasis of colon adenocarcinoma. Methods: The expressions of OPN, ZO-1, and E-cadherin were examined in 54 cases of adenoma and 67 cases of adenocarcinoma of the colon by immunohistochemical staining. Results: The expression of OPN in colon adenocarcinoma correlated with staging (p=0.012) and distant metastasis (p=0.021). The expression of ZO-1 was closely related with tumor cell differentiation (p<0.001), and the reduced expression of E-cadherin was associated with tumor cell differentiation (p=0.05) and lymph node metastasis (p<0.001). Co-expression of ZO-1 and E-cadherin was significantly associated with tumor cell differentiation, and the expressions of ZO-1 and E-cadherin were reduced or lost in all cases (5 cases) of poorly differentiated adenocarcinoma. Conclusions: Our data suggest that OPN is involved in the process of invasion and metastasis of colon adenocarcinoma, and ZO-1- and E-cadherin-mediated cell adhesion may play an important role in the differentiation of colon adenocarcinoma.