Objective: To evaluate the outcome of reoperations in patients with duodenopancreatic neuroendocrine tumors (PETs) in a tertiary referral center. Summary Background Data: The management of reoperations in PETs is still controversial. Methods: A total of 125 patients with PETs that underwent surgery between 1987 and 2004 at our institution were retrospectively evaluated. The diagnosis of PETs was based on clinical symptoms, biochemical tests, and histopathology. Patients with at least one reoperation were analyzed regarding clinical characteristics, pathology, operations, and long-term follow-up. Results: A total of 33 patients with a median age of 42 years were identified for this study: 13 patients had gastrinomas, 12 patients had nonfunctional islet cell tumors, 6 patients had insulinomas, and 2 patients had vipomas; 24 patients had sporadic NETs, 9 patients had a MEN-1-syndrome; 27 patients had histologically verified malignant tumors; 33 initial operations and 50 reoperations were performed. The initial procedures comprised 27 resections of the primary tumor and 6 explorative laparotomies; 28 of all reoperations were resections of distant metastases, including 15 liver resections; 19 resections of the pancreas or duodenum were performed during reoperations. The overall morbidity and mortality was 45% and 4.8%, respectively. After a median follow-up of 124 months (range, 16–384 months), 27 of 33 patients are still alive, 12 without evidence of disease. All 6 patients with benign tumors are still alive. The 5-, 10-, and actuarial 25-year survival rate for patients with malignant tumors were 81%, 72%, and 36%, respectively. The survival rate was significantly related to the patients age at time of initial operation and better in patients younger than 50 years compared with patients older than 50 years (P = 0.0007), and the presence or development of metastases (none or lymph node metastases versus distant metastases: P = 0.01). Conclusion: We show that an aggressive surgical approach leads to long-term survival in patients with malignant PETs. Although long-term cure can only be achieved in a proportion of patients with malignant PETs, significant long-term palliation can be achieved.

Background and aims: There are no chemopreventive strategies for pancreatic cancer or its precursor lesions, pancreatic intraepithelial neoplasia (PanINs). Recent evidence suggests that aspirin and inhibitors of angiotensin-I converting enzyme (ACE inhibitors) have potential chemopreventive properties. In this study, we used a genetically engineered mouse model of pancreatic cancer to evaluate the chemopreventive potential of these drugs. Methods: Drug treatment was initiated at the age of 5 weeks. LsL-Kras ^G12D ; Pdx1-Cre or LsL-Kras ^G12D ; LsL-Trp53 ^R172H ; Pdx1-Cre transgenic mice were randomly assigned to receive either mock treatment, aspirin, enalapril, or a combination of both. After 3 and 5 months, animals were killed. The effect of aspirin and enalapril was evaluated by histopathological analyses, immunostaining, and real-time PCR. Results: After 3 and 5 months of treatment, enalapril and aspirin were able to significantly delay progression of mPanINs in LsL-Kras ^G12D ; Pdx1-Cre mice. Furthermore, development of invasive pancreatic cancer in LsL-Kras ^G12D ; LsL-Trp53 ^R172H ; Pdx1-Cre transgenic mice was partially inhibited by enalapril and aspirin. Invasive pancreatic cancer was identified in 15 of 25 (60%) LsL-Kras ^G12D ; LsL-Trp53 ^R172H ; Pdx1-Cre untreated control mice, but in only three of 17 (17.6%, p=0.01) mice treated with aspirin, in four of 17 (23.5%, p=0.03) in mice treated with enalapril alone, and in five of 16 (31.2%, p=0.11) mice treated with a combination of both drugs. Using real-time PCR we found a significant downregulation of the target genes VEGF and RelA demonstrating our ability to achieve effective pharmacological levels of aspirin and enalapril during pancreatic cancer formation in vivo. Conclusion: Using a transgenic mouse model that imitates human pancreatic cancer, this study provides first evidence that aspirin and enalapril are effective chemopreventive agents by delaying the progression of PanINs and partially inhibiting the formation of murine pancreatic cancer. This study together supports the hypothesis that aspirin and ACE inhibitors might be a valid chemopreventive strategy.

Background: Epithelial and mesenchymal transitions (EMT) are essential for embryonic development and progression of non-invasive tumor cells into malignant, metastatic carcinomas. During embryogenesis, the parathyroid glands develop from pharyngeal pouches and migrate to their final destinations, densely enclosed by mesenchymal neural crest cells. In this study, we examined the expression of the EMT markers Snail, Twist and E-cadherin in normal parathyroid glands and benign and malignant parathyroid diseases.Methods: Using immunohistochemistry, we compared expression of E-cadherin, Snail and Twist in 25 patients with parathyroid adenoma, 25 patients with parathyroid hyperplasia, and nine patients with parathyroid cancer with normal parathyroid glands.Results: Normal parathyroid glands, parathyroid adenomas, and parathyroid hyperplasias showed a typical membranous E-cadherin staining pattern. Expression of Snail was found in 22/25 parathyroid adenomas and in all parathyroid hyperplasias. Twist was expressed in 22/25 of parathyroid adenomas and in 20/25 parathyroid hyperplasias. Snail and Twist positive cells were homogeneously distributed throughout the gland. However, in all nine parathyroid carcinomas, membranous E-cadherin staining was lost. In addition, the expression pattern of Snail and Twist was changed and mostly limited to the invasive front of cancer tissue samples.Conclusion: Expression of Snail and Twist at the invasive front and consecutive loss of E-cadherin in parathyroid carcinomas suggests a key role of EMT in the tumorigenesis of this cancer. The unique expression pattern could help to distinguish between an adenoma and a non-metastatic carcinoma. Loss of E-cadherin and change of the expression pattern of Snail and Twist together should result in anen blocresection or a close follow-up.

Tissue inhibitor of metalloproteinase-3 (TIMP3) antagonizes matrix metalloproteinase activity and can suppress tumor growth, angiogenesis, invasion, and metastases. In the present study, the involvement of TIMP3 in the tumorigenesis of 34 pancreatic adenocarcinomas was evaluated. Immunohistochemistry, methylation-specific PCR, and RNA expression analysis (RT-PCR) of TIMP3 were performed in 34 resected and microdissected primary pancreatic adenocarcinomas. Immunohistochemistry showed loss or strongly reduced protein expression in 17 of 34 pancreatic adenocarcinomas (50%) that corresponded to loss of TIMP3-RNA-expression. Promoter hypermethylation was identified in 2 of 34 tumors (6%). It was tumor specific and corresponded to a loss of TIMP3 protein expression. TIMP3 alterations did not correlate with any clinical feature such as tumor size or survival. TIMP3 seems to play an important role in the tumorigenesis of primary pancreatic adenocarcinomas. In contrast to other tumors, hypermethylation seems not to be the key mechanism for the inactivation of TIMP3. Other methods of gene inactivation need to be identified.