Praomys (Mastomys) natalensis: a model for gastric carcinoid formation.

The gastric carcinoid tumors of Praomys (Mastomys) natalensis have been reviewed with respect to histogenesis, development, biochemistry, and morphological properties. Multicentric gastric carcinoids frequently develop in the oxyntic mucosa of aging Mastomys. The development of these tumors can be significantly enhanced by drug-induced hypergastrinemia, e.g., histamine2-receptor blockade. Spontaneous and drug-induced gastric carcinoids are endocrine in nature, as evidenced by their argyrophilic staining properties and chromogranin A content. They are also rich in histidine decarboxylase activity and produce large amounts of histamine, although other hormones, such as peptide YY and enteroglucagon, have also been demonstrated in these tumors. Ultrastructurally, gastric carcinoids are composed of tumor cells with typical secretory granules resembling those of enterochromaffin-like (ECL) cells. A close examination of the gastric carcinoids in Mastomys reveals striking similarities with gastric carcinoids developing in humans suffering from chronic atrophic gastritis type A or from the Zollinger-Ellison syndrome in combination with multiple endocrine neoplasia type 1 (MEN-1). Both these conditions are associated with hypergastrinemia and a higher risk for developing multi-centric gastric carcinoids of ECL-cell origin. The Mastomys tumor model therefore appears to be a significant experimental model in which induction and formation of gastric carcinoid tumors can be studied.     

Natural history, clinicopathologic classification and prognosis of gastric ECL cell tumors.

A series of 50 gastric endocrine tumors classified according to Rindi et al. [1] comprised 12 small cell neuroendocrine carcinomas (NEC) and 38 ECL cell carcinoids, of which 22 associated with type A chronic atrophic gastritis (A-CAG), eight with hypertrophic gastropathy due to combined Multiple Endocrine Neoplasia and Zollinger/Ellison syndrome (MEN/ZES), and eight sporadic. Variables found to predict tumor malignancy were: size > 2 cm, > 2 mitoses and > 130 Ki67 positive cells/10 high power fields (HPF), grade 2 or 3 histology, angioinvasion, p53 protein nuclear accumulation, and the presence of a single tumor. None of these factors increased significantly the predicting ability of tumor classification itself, although grade 2 + 3 shows 100 percent negative predictive value and Ki67 and angioinvasion 100 percent positive predictive value. When the mostly non-malignant A-CAG and MEN-ZES tumors were analysed against the mostly malignant sporadic and NEC tumors, a positive predictive value of 90 percent and a negative predictive value of 93 percent was obtained. Investigation of a larger tumor series is under way with the aim to develop an optimal model for prognostic evaluation of gastric endocrine tumors.     

Acid Secretion and Serum Gastrin Levels in the Zollinger-Ellison Syndrome

Thirteen cases of patients with the Zollinger-Ellison syndrome were reviewed. In two cases the diagnosis was made by incidental biopsy of small liver nodules at operation for peptic ulcer disease.Seven patients had gastric secretory tests which showed a basal acid output to maximum acid output ratio of more than 65 percent. Five patients had bao:mao ratios less than 50 percent.A 30-month interval between incidental discovery of tumor and clinically evident disease was observed in two patients. Recurrence of symptoms after excision of tumor was noted after a similar interval in another case.Serum gastrin levels, before total gastrectomy, were elevated in all cases. The lowest preoperative level in this series of patients was 550 picograms per ml (normal 100 to 150 picograms). They were diagnostic in two patients with normal gastric secretory studies. The levels fell to normal following total gastrectomy in six patients. Two patients still had elevated levels five years and 14 years after total gastrectomy. One was discovered to have a parathyroid adenoma with hypercalcemia.Total gastrectomy was curative in all the patients with the Zollinger-Ellison syndrome; lesser operations were not.     

Is gastrinoma a medical disease?

Zollinger-Ellison syndrome (ZES) is a rare disease. Its management concerns symptoms related to the gastric acid overproduction that characterizes the syndrome and to the gastrin-producing tumor(s) usually located in the duodenal wall and/or the endocrine pancreas. Acid hypersecretion is now controlled by the use of powerful antisecretory agents. Management of the malignant process(es) has become the primary goal of modern strategy: it aims first at curing the disease and second at prolonging patient survival by prevention of hepatic metastasis. In patients with the sporadic form of the disease and without liver metastases, it is currently possible to localize and to surgically remove the endocrine tumor(s). This progress has been made feasible by refinements in modern medical imaging. At present, however, disease cure, even in the most favorable conditions, is not be greater than 30 to 50 percent at five years. In patients with ZES integrated in the context of multiple endocrine neoplasia type I, disease cure rate is extremely low, although occasional patient survival can be as good or even better than in the sporadic group. Disseminated malignancy (liver and/or extra-abdominal lymph nodes or bone localization) remains the principal determinant of early death. Surgical treatment is usually precluded in such cases. Liver transplantation has not been successful in these patients.     

Pathogenesis of ECL cell tumors in humans.

In ECL cell tumors developed in the setting of hypergastrinemic conditions (ECL cell carcinoids type 1 and 2), hypergastrinemia is the dominant agent acting as a promoter in all steps (hyperplasia-dysplasia-neoplasia) of the tumorigenic sequence. In contrast, it apparently lacks transforming properties as shown by the absence of ECL cell carcinoids in patients exposed to hypergastrinemia alone, i.e., those with sporadic Zollinger-Ellison syndrome. The potential transforming factors include: the allelic loss of the MEN-1 suppressor gene in the genetically predisposed MEN-1 patients, an alteration that may induce ECL cell tumors even in the absence of hypergastrinemia; the still unknown factor(s) associated with atrophic corporal gastritis; agents whose role in the induction of human ECL cell tumors is still unclarified, such as basic Fibroblast Growth Factor, human Chorionic Gonadotropin-alpha and Transforming Growth Factor-alpha; and agents having a favoring role on the ECL exposure to mitogens such as BCL-2. No information is currently available on the pathogenesis of gastrin-independent, sporadic ECL cell carcinoids (type 3) or of gastric neuroendocrine carcinomas.     

Diagnosis and treatment of ECL cell tumors.

The diagnosis of ECL-omas is easy to perform. In patients with Zollinger-Ellison syndrome (ZES), ECL-omas are almost always observed in the setting of multiple endocrine neoplasia type I. In patients without ZES, the first step is to discard non-gastrin-related sporadic ECL-omas whose prognosis is poor. By contrast, prognosis of ECL-omas in patients with ZES or chronic atrophic gastritis is good. Metastases are rare, and tumor-related deaths are exceptional. In both conditions, ECL-omas measuring less than 1 cm should be treated by endoscopic polypectomy and survey. Treatment modalities (surgery, endoscopic polypectomy) for larger tumors are still discussed. The impact of endoscopic ultrasonography on the therapeutic decision has not yet been evaluated. Considering the good prognosis of these tumors, aggressive surgery could be limited to selected patients. Multicentric studies should be undertaken to determine the best treatment modalities.     

Biomarkers and molecular imaging in gastroenteropancreatic neuroendocrine tumors

Neuroendocrine gastrointestinal and pancreatic tumors (GEP-NETs) are a heterogenous group of cancers with various clinical expressions. All tumors produce and secret various amines and peptides, which can be used as tissue and circulating markers. Chromogranin A (CgA) is a general tumor marker stored in secretory granules within the tumor cell and released upon stimulation. CgA is the best general tumor marker at the moment, expressed in 80-90% in all patients with GEP-NETs. CgA and NSE are used as tissue markers for the delineation of the neuroendocrine features of the tumors, but recently also the proliferation marker Ki-67 has been included in the standard procedure for evaluation of the proliferation. GEP-NETs are classified into well differentiated neuroendocrine tumors (Ki-67<2%), well-differentiated neuroendocrine carcinoma (Ki-67 2-20%), poorly differentiated neuroendocrine carcinoma (Ki-67>20%). The molecular imaging of NETs is based on the ability of these tumor cells to express somatostatin receptors as well as the APUD features. Octreoscan has been applied for imaging and staging of the disease for more than 2 decades and will nowadays be replaced by 68Ga-DOTA-Octreotate, with higher specificity and sensitivity. 18Fluoro-DOPA and 11C-5HTP are specific tracers for NETs with high specificity and selectivity. A new potential biomarker is auto-antibodies to paraneoplastic antigen MA2, which might indicate early recurrence of carcinoids after surgery with a curative intent. Circulating tumor cells (CTC) have been applied in GEP-NETs quite recently. There is still an unmet need for new markers.     

Distinct patterns of chronic gastritis associated with carcinoid and cancer and their role in tumorigenesis.

A series of 60 gastric endocrine tumors comprised 44 body-fundus argyrophil carcinoids, of which 23 arose in a background of hypergastrinemia and type A chronic atrophic gastritis (A-CAG), mainly with histologic patterns suggestive of an autoimmune process. Only 22 percent (compared with 19 percent of 58 tumor-free A-CAG cases) of 36 carcinoids and 21 percent of 19 A-CAG carcinoids investigated had Helicobacter pylori (HP) colonization, against 50 percent of 14 CAG-associated neuroendocrine carcinomas or mixed endocrine-exocrine tumors, 84 percent of 150 cases with early gastric cancer (p < 0.001 versus carcinoids), mostly with B- or AB-type CAG, 76 percent of 97 tumor-free AB-CAG, and 95 percent of 151 tumor-free B-CAG cases. Secondary hypergastrinemia and local mechanisms activated by chronic autoimmune gastritis are among factors involved in the pathogenesis of relatively indolent CAG-associated carcinoids, whereas active HP gastritis in cooperation with environmental carcinogens may likely cause more severe epithelial transformation, leading to ordinary cancer and, possibly, to neuroendocrine carcinomas or mixed endocrine-exocrine tumors.     

Zollinger-Ellison Syndrome due to Primary Gastrinoma of The Extrahepatic Biliary Tree: Three Case Reports and Review of Literature

ObjectiveTo report 3 cases of primary neuroendocrine tumors (PNT) of the extrahepatic biliary tree (EHBT) in patients with Zollinger-Ellison syndrome (ZES), 2 of whom had multiple endocrine neoplasia type 1 (MEN 1).MethodsThree new cases of gastrin-producing tumors of the EHBT are presented, and the pertinent literature relating to PNT of the EHBT is reviewed.ResultsEighty-one previous cases of PNT of the EHBT have been reported in the world literature, 7 of which were hormonally active and associated with peptic ulcer disease, diarrhea, or ZES. Three additional patients presented to us with ZES due to PNT of the EHBT. One patient with MEN 1 was treated with a Whipple procedure for a common bile duct gastrinoma. A second patient underwent left hepatectomy with resection of the confluence of the right and left hepatic ducts for a primary left hepatic duct gastrinoma. The second patient with MEN 1 underwent resection of a gastrinoma at the junction of the cystic duct and the common bile duct.ConclusionAlthough PNT of the EHBT are uncommon, the association with ZES is even more so. Often, nonfunctioning tumors are diagnosed late in the course of the disease from symptoms related to biliary obstruction. Patients with ZES may be diagnosed earlier because of symptoms resulting from gastrin excess. Surgical resection is the only chance for cure and is often helpful in the palliation of symptoms. (Endocr Pract. 2009;15:737-749)     

Interferons in the management of neuroendocrine tumors and their possible mechanism of action.

Alpha interferons at doses of 3-9 MU subcutaneously, three to seven times/week, have been administered to 32 patients with malignant endocrine pancreatic tumors. The objective biochemical response rate was 63 percent with a median duration of 20.5 months. Significant reduction of tumor size was only noticed in 20 percent of the patients. Alpha interferon administered to 111 patients with malignant carcinoid tumors showed objective biochemical responses in 42 percent of the patients with a median duration of 32 months. Another 39 percent of the patients showed stabilization of disease without any further tumor growth. Subjective improvement was noticed in 70 percent of the patients. When survival data are analyzed in patients with malignant carcinoid tumors, the median survival from start of treatment was 80+ months in the group of patients treated with alpha interferon, which should be compared with only eight months in a historical group treated with chemotherapy (streptozotocin plus 5-fluorouracil). The adverse reactions to alpha-interferon treatment are dose-dependent and include, mainly, flu-like symptoms, fatigue, and low-grade weight loss. Autoimmune reactions are noted in about 20 percent of the patients. Patients treated with recombinant alpha interferons might develop neutralizing interferon antibodies (6-27 percent), which abrogate the anti-tumor response. The anti-tumor effect in neuroendocrine tumors includes anti-proliferation, apoptosis, differentiations, and cytotoxic/cytostatic effects. Furthermore, immunomodulation is obtained by increased expression of class I antigens on tumor cells. Four patients also developed antibodies directed against carcinoid tumor cells. Alpha interferons induce several nuclear enzymes such as 2'-5'-A synthetase, p-68 kinase, and Mx-A proteins, which are involved in a downregulation of expression of growth factors, oncogenes, and peptide hormones, leading to anti-proliferation and/or apoptosis. The response to alpha-interferon treatment might be predicted by analysis of the induction of 2'-5'-A synthetase in samples from neuroendocrine tumors. Stimulatory tests of hormone secretion, such as meal stimulation of pancreatic polypeptide secretion or secretin test, clearly demonstrate a normalization during alpha-interferon treatment, which might depend on reduced peptide production and/or secretion but also on eradication of malignant cell clones. In summary, alpha interferons have demonstrated significant anti-tumor effects in patients with malignant neuroendocrine gut and pancreatic tumors. The adverse reactions are dose-dependent and manageable. The anti-tumor effects of alpha interferons are pleiotropic and include several direct effects on tumor cells but also immunomodulation.     

The presence of somatostatin receptors in malignant neuroendocrine tumor tissue predicts responsiveness to octreotide.

In 77 percent of patients suffering from a malignant carcinoid syndrome, administration of the somatostatin analog, octreotide (SMS 201-995, Sandostatin) induced clinical improvement coupled with a decrease in 24-hour urinary 5-hydroxyindole acetic acid (5-HIAA). This finding prompted an evaluation to determine the correlation between the presence of somatostatin receptors in tumor tissue and the response to octreotide in patients with advanced, metastatic, neuroendocrine tumors. In tissues of 31 tumors (20 carcinoid, eight islet-cell carcinoma, three medullary thyroid carcinomas), the presence of somatostatin receptors was analyzed by binding of the somatostatin analog 125I-Tyr3-SMS 201-995 and autoradiography. Receptors were detected in 16 of 20 samples of carcinoid tissues; all but one patient with receptor-positive tumors improved clinically after treatment with octreotide, and the urine 5-HIAA level was reduced a median of 63 percent (range, 39-94 percent) compared to values before treatment. Of the receptor-negative carcinoid patients, only one showed clinical improvement, which was minimal, and there was a negligible reduction in 5-HIAA after octreotide therapy. All eight patients with metastatic islet-cell carcinomas were positive for somatostatin receptors. Symptomatic improvement and a > 50 percent decrease in the level of at least one of the pathologically elevated marker hormones was seen in all eight. None of the three patients with medullary carcinoma of the thyroid had a decrease in calcitonin, and all three were initially somatostatin receptor-negative. We conclude that the presence of somatostatin receptors in malignant neuroendocrine tumor tissue appears to correlate with the response to octreotide therapy. Analysis of somatostatin receptors in malignant neuroendocrine carcinoma tissue should be included in future prospective clinical trials of this synthetic peptide.     

Effects of neuromedin B and GRP-10 on gastrin and insulin release from cultured tumor cells of a malignant gastrinoma

A study relating to gastrin release from gastrinoma cells by neuromedin B and C-terminal decapeptide of gastrin releasing peptide (GRP-10) has not yet been reported. Therefore, we studied the effects of neuromedin B and GRP-10 on gastrin release from cultured dispersed cells prepared from both the primary tumor in the pancreas and the metastatic tumor in the liver from a case of malignant Zollinger-Ellison syndrome. Both the primary and metastatic tumors obtained by a curative operation contained similar concentrations of gastrin and glucagon, whereas the primary tumor contained 10 times more insulin than the metastatic tumor. Gastrin release from cultured cells of both tumors was suppressed by 0.1 and 10 nM neuromedin B and tended to be suppressed by 0.1-10 nM GRP-10. However, insulin release from cultured cells of the pancreatic tumor was stimulated by GRP-10, but not by neuromedin B. These results might suggest that receptor function for the bombesin family peptides is abnormal in gastrinoma cells in both primary and metastatic tumors, and that a major source of insulin secretary cells is the contaminated normal islet cells in the primary tumor.     

Adrenomedullin is a novel marker of tumor progression in neuroendocrine carcinomas.

Adrenomedullin is a multi-functional polypeptide hormone. Its involvement in angiogenesis and vasodilator action support the hypothesis that adrenomedullin may be a secretory product of neuroendocrine tumors and contribute to tumor progression. Plasma levels of adrenomedullin were measured by radioimmunoassay in 46 patients with neuroendocrine carcinomas of the gastroenteropancreatic and bronchial system. Tissue expression of adrenomedullin was studied using monoclonal antibodies on pretreated paraffin embedded tissues in a group of 31 patients. Adrenomedullin plasma levels were significantly elevated in patients compared to healthy age-matched controls (p < 0.001). The highest plasma levels were found in patients with neuroendocrine carcinomas of bronchial, midgut and unknown origin. Patients with progressive disease had higher plasma levels than patients with stable disease (p < 0.001). Of the examined tumor samples, 55 % showed cytoplasmic staining for adrenomedullin > 5 % of the total tumor area. Plasma levels and tissue expression of adrenomedullin did not correlate with functional activity of the tumors or presence of the carcinoid syndrome, but did with tumor progression (p < 0.001 and p < 0.014). In conclusion, plasma and tissue expression of the angiogenic peptide adrenomedullin are predictive of tumor progression in patients with neuroendocrine carcinomas. Adrenomedullin might represent a useful prognostic marker in patients with neuroendocrine carcinomas.     

Experience of Ectopic Adrenocorticotropin Syndrome: 88 Cases With Identified Causes

ObjectiveEctopic adrenocorticotropic hormone syndrome (EAS) is a rare cause of Cushing's syndrome and diagnosis and management remain challenging. The aim of this study was to present the clinical spectrum of a group of EAS cases in a single center to explore better management strategies.MethodsA retrospective study was conducted to identify 88 confirmed EAS cases at our hospital from 1984 to 2019. The clinical, biochemical, imaging, and pathological features were analyzed.ResultsOf the 88 eligible patients with EAS, 38 (43.2%) cases of pulmonary neuroendocrine tumors (NETs) and a larger number of thymic/mediastinal NETs (29 cases, 33%) were identified. The clinical and biological features of EAS and Cushing's disease overlapped but were more severe in EAS. Inferior petrosal sinus sampling (97.4%) and computed tomography (85.4%) provided the highest positive diagnostic accuracy. Computed tomography is also a useful tool to identify tumors in chest cavity compared with nonchest lesions (91.2% vs 57.1%). Although a greater tumor size (4.54 cm vs 1.44 cm) and higher rate of insuppressible high-dose dexamethasone suppression test (83.3% vs 51.5%) were found in thymic/mediastinum NETs than in pulmonary NETs, the level of hormone production had no difference.ConclusionEAS had more common and severe clinical presentations than Cushing's disease, and multiple imaging approaches are required for reliable diagnosis. A higher proportion of thymic/mediastinal NETs was found in our study. For patients without a certain tumor source, long-term follow-up and further evaluations are needed.     

The WDHA syndrome: clinical and laboratory data on 28 Japanese cases

During the period between 1967 and 1983, there were 28 WDHA patients in Japan. Clinically, these patients were not very different from those reported in western countries, but we have been able to add a few observations as follows. First, the WDHA patients with pancreatic endocrine tumors and those with neuroblastic tumors were present in almost equal numbers. Second, fluctuating hypercalcemia was often observed in patients with this syndrome, but it was not observed in any watery diarrhea due to the other etiologies. Third, the WDHA patients who have multiple endocrine neoplasia (MEN) type 1 have multiple tumors in the pancreas, indicating that the patients with MEN should be managed in a different manner in regard to determining tumor location as well as applying surgical treatment. When various types of tumors were examined for VIP content, it was found that many tumors have the potential to produce VIP, and when VIP is produced in large amounts, plasma VIP levels become elevated, resulting in the WDHA syndrome.     

Multiple primary malignant neoplasms in England and Wales, 1971-1981

In the period 1971-81, more than 1.9 million persons were registered with a malignant neoplasm among the 49.2 million population of England and Wales. For 63,536 people, two or more tumor registrations (multiple tumor records) have arisen in that period. Because of the structure of the National Cancer Registration scheme, some errors in registration are inevitable, particularly duplicate registration of a single tumor by adjacent regional cancer registries. A pilot study showed that 61 percent of multiple records would represent true multiple primary malignancy, and that these records could be readily separated from registration errors. After abstraction of identifying codes from each tumor, 129,047 tumors involved in 63,536 multiple records were matched to the national cancer file, and the full data set extracted for successfully matched tumors. Person-years data were extracted for the 1.8 million tumors not involved in a multiple record. Eleven percent of multiple records were not completely matched, and a further 16 percent were excluded on SEER criteria, or as probable registration errors, leaving 46,155 multiple primary tumors for further analysis. Over 3 million person-years at risk of a second tumor were accrued. The overall risk of a second tumor at any site before age 85 was 0.77 for males and 0.80 for females, after exclusion of second tumors observed within 12 months of the first. The risk of a new primary apparently decreased with increasing duration of survival, a trend which may be due in part to under-registration of second tumors in the early 1970s and an improvement in linkage since 1971.     

The immune system in neuroendocrine tumors

During the last 30 years the incidence of neuroendocrine tumors has increased considerably and the overall 5-year survival rate has not changed substantially. Conventional therapeutic approaches appear to show an unsatisfactory effect in the more insidious forms of malignancies. Hence, attempts were made to direct the patient's own immune system against cancer by vaccinating against different tumor antigens. Up to date, only sporadic achievements were demonstrated in the majority cases of vaccination trials. One of the main hindrances to a successful vaccination comprises tumor-immune-escape mechanisms. This review focuses on the current knowledge concerning tumor immunoevasion strategies and the immune system in neuroendocrine tumors.     

两种内镜手术对消化道神经内分泌肿瘤的切除效果及安全性评价

目的:探讨内镜下两种手术方法对消化道神经内分泌肿瘤的切除效果和安全性。方法:选取64例消化道神经内分泌肿瘤患者,随机分为A组和B组,每组各32例。A组接受内镜下黏膜切除术,B组接受内镜下黏膜剥离术。分析和比较两组所切除组织的病理学检查结果、手术时间、切除肿瘤的直径和厚度、治疗费用、住院时间、肿瘤完全切除率、垂直切缘阴性率以及并发症的发生率。结果:A组的手术时间为(8.95±1.63) min,治疗费用为(2127.70±468.31)元,均显著少于B组(P0.05);两组患者切除肿瘤直径和厚度、住院时间、垂直切缘阴性率对比差异均没有统计学意义(P0.05);B组的肿瘤完全切除率为93.75%,显著高于A组(P0.05);A组并发症发生率为3.13%,显著低于B组(P0.05)。结论:两种内镜下手术方式均可有效清除消化道神经内分泌肿瘤病灶。内镜下黏膜切除术的手术时间、费用及并发症的发生率更少低,而内镜下黏膜剥离术能够更彻底地清除肿瘤组织。