Expression of cluster of differentiation 74 in gallbladder carcinoma and the correlation with epithelial growth factor receptor levels.

Cluster of differentiation 74 (CD74), a transmembrane glycoprotein, has been previously reported to be important in the pathogenesis of several cancers, including hematological malignancies and solid tumors. The present study analyzed the significance of CD74 in gallbladder carcinomas (GBCs) and indicated the correlation of CD74 expression with epithelial growth factor receptor levels. Immunohistochemistry (IHC) was used to examine the expression of CD74 in GBC and normal gallbladder tissues, and western blotting was used to investigate whether CD74 expression varied in well-, moderately- and poorly-differentiated tumors. The correlation between the expression of CD74 and epithelial growth factor receptor levels was studied using the Spearman's rank correlation coefficient. The results of the IHC analysis revealed that CD74 was not expressed in the normal gallbladder tissues, and the mean integrated optical density value of CD74 in the poorly-differentiated tissues was increased compared with that in the well- and moderately-differentiated tissues. The results of the western blotting were consistent with the results of the IHC. The expression of CD74 was positively correlated with epithelial growth factor receptor levels (r=0.607; P<0.05). These results indicate that CD74 may be important in the progression of GBC.