[Proteomic study of gallbladder cancer, with special reference on the expression and significance of annexin A3]

To explore the potential molecular targets for diagnosis and treatment of gallbladder cancer by analyzing and comparing the proteomes expressed in human gallbladder cancer and benign gallbladder tissues.

The proteins expressed were analyzed using two-dimensional gel electrophoresis. The differentially expressed proteins in tumors were also analyzed by mass spectrometry (MS). AnnexinA3 expression was examined by streptavidin peroxidase immunohistochemical technique on paraffin-embedded tissue sections from 50 patients of gallbladder cancer and 38 cases of chronic eholecystitis.

Protein extracts of individual sample in each type of tissues were separated on two-dimensional gels. There were forty six differentially expressed proteins in the tissue samples of gallbladder cancer. Seventeen proteins were successfully identified by MS, in which nine proteins were overexpressed in tumors and the other eight proteins were underexpressed. The positive expression rates of annexinA3 in gallbladder cancer was significantly higher than that in chronic cholecystitis, and the difference was statistically significant (74.0% vs 21.1%, P < 0.01). In the gallbladder cancer, no correlation was obtained between annexinA3 and age, gender or histologicl type (P > 0.05), but overexpression of annexinA3 correlated significantly with those cases with a lower histological grading (40.0% vs 82.5%, P < 0.05); lymph node or distant metastasis (40.9% vs 100%, P < 0.05); or a shorter survival time after operation (50.0% vs 93.8%, P < 0.05).

Significant discrepancies in protein expression exist among gallbladder cancer and benign gallbladder tissues. AnnexinA3 plays an important role in the initiation and progression of human gallbladder cancer.