Geminin Expression in Pancreatic Neuroendocrine Tumors Possible New Marker of Malignancy

Objectives: We evaluated geminin labeling index (LI) as a new prognostic indicator of pancreatic neuroendocrine tumor. Methods: Twenty-seven patients who underwent surgery were retrospectively referred. Labeling indices for geminin and Ki-67 were calculated and compared with clinicopathologic factors. Then, the concordance of positivity between 2 LIs was evaluated using the color difference quotation. Results: The median (range) of LIs for geminin and Ki-67 was 1.0% (0.05%-14.9%) and 1.5% (0.02%-8.8%), respectively. When the high LI was defined as more than 2.0% according to the receiver operating characteristic curves determining the metastasis, both geminin LI (hazard ratio [HR], 31.382; 95% confidence interval [CI], 3.177-309.99; P = 0.003) and Ki-67 LI (HR, 6.182; 95% CI, 1.221-31.298; P = 0.028) were significant risk factors of recurrence in the univariate analysis. The Kaplan-Meier curves consistently exhibited the superiority of geminin LI (log rank, P < 0.001) to Ki-67 LI (log rank, P = 0.041) in predicting the disease-free survival. In the color difference quotation, the median Delta E of geminin stain (16.12; range, 5.8-41.9) was significantly larger than that of Ki-67 stain (13.17; range, 3.4-37.9). Conclusions: The geminin LI was suggested to be more closely correlated with outcome and had more consistent positivity than the Ki-67 LI.