The Expression And Clinicopathological Role Of CD97 And Its Cellular Ligand CD55 In Gastric Carcinoma

Aims: To investigate the expression of CD97EGF and its cellular ligand CD55 protein in gastric carcinoma tissues. To determine whether the expressions of these two molecules are involved in the clinicopathological features of the gastric carcinomas patients.Methods: A total of 35 gastric carcinomas and its corresponding marginal and normal specimens were investigated by RT-PCR, Western blot and immunohistochemistry. Results: mRNA levels of CD97EGF and CD55 were higher in tumors than those on the margin and normal epithelial mucous tissues (p<0.05). However, the expression levels of CD97EGF and CD55 mRNA had no correlations with clinicopathological features of the gastric carcinoma patients. All three groups of specimens were of immunoreactive with CD97EGF and CD55 protein. Strong and specific immunoreactivities of CD97EGF located on the mucosal epithelial of marginal basal membrane. There was marked difference between each of two groups of all three sites among tumor, margin and normal epithelial mucous tissues (p<0.05). The expression of CD97EGF in margin showed marked difference between the two groups of patients with the depth of tumor invasion T1 or T2, T3, T4 (p<0.05) and stage I or II,III, IVof gastric carcinomas(p<0.05). The positive-staining of CD55 in tumor tissues was lower man inmargin and normal epithelial mucous tissues (p<0.05). The positive expression of CD55 protein was highly correlated with CD97EGF, the values of r were 0.697 (tumor), 0.514 (margin) and 0.811 (normal) respectively. The results from Western blot showedthat the densities of CD97EGF (x ±s) were 0.3081 ±0.1778(tumor), 0.4130 ±0.2569(margin), 0.3534 ± 0.2178(normal); CD55 (x ±s) were 0.2875 ±0.1414(tumor), 0.3981 ±0.1988(margin), 0.4097±0.2534(normal) respectively。 The Correlations analyses of the expressing levels of these two proteins showed the values were r=0.47(tumor), r=0.54(margin), r=0.59(normal)。 Western blot analyses conformed this kind of expression and distribution patterns of CD97EGF and CD55 that is the highest expressing level of CD97EGF in margin and CD55 in normal tissues. Conclusions: CD97EGF may play a role in the development and invasion of gastric carcinomas by binding its cellular ligand CD55. The expression of CD97EGFon the margin could be referred as molecular edge of gastric carcinomas.