| Introduction:Colorectal cancer is one of the commonest tumors in china,and its morbidity is still increasing.The 5-year survival rate after curative resection is still about 50%,although the operation-based comprehensive therapieshave greatly improved the prognosis of colorectal cancer in recent years.The two major features of malignant tumors are infiltration and metastasis, which are the direct causes of death of post-operative patients with cancer. Elucidating the molecular biological events which influence the prognosis of colorectal cancer,predicting the infiltrated and metastatic tendency of colorectal cancer,with can direct the doctor to use more effective comprehensive therapies,and then reduce the post-operative recurrence or metastasis and increase post-operative survival rate.At the same time, studies of the molecular biological mechanism of the infiltration and metastasis can provide theoretical basis of gene therapy to colorectal cancer. Infiltration of tumors is a process of interaction between tumor cells and extracellular matrix. It includes three steps which are cell adhesion, metrix degredation and cell migration.Disruption of cell-cell adhesion has been considered the first step in the complicated process of tumor metastasis. In recent years,the cell adhesion molecules discovered included integrins,CD44, cadherins,irnmunoglobulin superfamily,selections etc.As one of the cell adhesion molecules, E-CD is a transmembrane glycoprotein that is responsible for calcium-dependent intercellular adhesion by homophilic interaction.It is expressed in the epithelium and placenta where it maintains the epithelial structure and polarity. E-CD is mainly distributed at the cell border and in particular at cell-cell adhesion areas.Cells without E-CD expression can not aggregate or adhere to each other.lt has been demonstrated the existence of lower E-CD expression in many human malignant tumors,and that there was a significant relationship between lower E-CD expression and infiltration.metastasis or prognosis of malignant tumors. Catenins are a group of undercoat proteins that interact with the intracellular domain of E-CD to form a complexes which is prerequisite for the function of E-CD. A number of in vitro studies have established that a -cat was molecule that suppressed infiltration and metastasis,and that abnormality of a -cat protein facilitated tumor cell dissociation,increased motility and invasiveness,and increased the possibility of distant metastasis. Most studies in vivo have also demonstrated the lower expression of a -cat in most human cancers,and that the lower expression of a -cat significantly correlated with less favorable clinicopathological features.However, studies on the relationship between E-CD or a -cat expression in colorectal cancer and tumor infiltration,metastasis and prognosis has not been reported in domestic documents to the date time.In the present study, we investigated the expression of E-CD and a -cat in colorectal cancer tissues by using immunohistochemical method (EnVision) to evaluate the relationship between the expression of E-CD ora -cat and infiltration,metastasis and prongosis in colorectal cancer,and to evaluate the clinical values of E-CD and a -cat in predicting the invasive,metastatic potential and prognosis of colorectal cancer,and to provide useful molecular biological indicators for comprehensive therapies to colorectal cancer.115 patients with colorectal cancer who underwent surgical resection at Zhejiang Provincial People's Hospital from January 1988 to December 1997 were admitted. A control group includes 10 normal colorectal mucosa and 19 colorectal adenomas.All cases were verified by operation and pathology.Of 126 patients, 115(91.3%) got follow-up.The median follow-up time was 50.93 months,with a range of 4 months to 142 months.The clinical staging was according to the Duke's classification.All the specimens were fixed in 10% formalin and embedded in paraffin.Consecutive sections from each specimen were stained with hemotoxy...
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