Cleaved caspase-3 immunocytochemical staining for pancreatic islets and pancreatic endocrine tumors: A potential marker for biological malignancy

Abstract

Aims: Involvement of caspase (C)-3 has been implicated in β cells from diabetic subjects. This study is aimed to immunocytochemically identify cleaved caspase-3 (CC -3) positive cells in pancreatic endocrine tumors (PE Ts) compared with control islets. Results: Control islets revealed some CC -3 positive cells, ranging 3.6 to 7.3% of total islet cells. Small islets in the pseudocapsule of PE Ts showed higher immunopositive cells at about 9% for CC -3, suggesting an accelerated apoptosis in these compressed, elongated islets before proceeding to imminent cell death. Majority of primary PE Ts except 9 cases were negative for CC -3 immunostaining: five insulinomas, one somatostatinoma, one gastrinoma and one pancreatic peptidoma (PP oma) were positive for CC -3. Methods: Using commercially available rabbit anti-CC -3, immunocytochemical staining was performed in 42 cases of PE Ts compared with control islets. Conclusions/Interpretation: Majority of primary PE Ts (28/37, 76%) were negative for CC -3, suggesting that majority of PE Ts are not on apoptotic program of the normal islets. Since 21 of 24 (88%) of potentially malignant primary non-β cell PE Ts were negative, whereas 5 of 12 (42%) benign insulinomas were positive for CC -3 immunostaining, CC -3 negative immunostaining may serve as a possible malignant marker for all PETs. © 2010 Landes Bioscience.