The relationship between MIB-1 proliferation index and outcome in pancreatic neuroendocrine tumors

The expression of the cell-cycle-associated Ki-67 antigen by MIB-1 monoclonal antibody was retrospectively assessed in 35 surgically resected neuroendocrine tumor specimens of the pancreas embedded in paraffin. The MIB-1 proliferation index was correlated with the classification of the neuroendocrine tumors of the pancreas proposed by Kloppel et al. Four prognostic factors showed a significant correlation with MIB-1: local invasion, metastases, tumor differentiation, and production of insulin. However, analysis by the Cox Proportional Hazards Regression Model showed that only local invasion was an independent predictor of outcome. Finally, our study showed a statistically significant increase in the number of deaths and a statistically significant decrease in survival time when the MIB-1 proliferation index was higher than 4%. We conclude that MIB-1 proliferation index is a simple and reliable tool to predict the clinical outcome of the neuroendocrine tumors of the pancreas. The index might be useful for determining the prognosis for an individual because of the significant decrease in survival when the index is higher than 4%.