Chromogranin A--biological function and clinical utility in neuro endocrine tumor disease

BACKGROUND

Neuroendocrine tumors (NETs) are a form of cancer that differ from other neoplasia in that they synthesize, store, and secrete peptides, e.g., chromogranin A (CgA) and amines. A critical issue is late diagnosis due to failure to identify symptoms or to establish the biochemical diagnosis. We review here the utility of CgA measurement in NETs and describe its biological role and the clinical value of its measurement.

METHODS

Literature review and analysis of the utility of plasma/serum CgA measurements in NETs and other diseases.

RESULTS

CgA is a member of the chromogranin family; its transcription and peptide processing are well characterized, but its precise function remains unknown. Levels are detectable in the circulation but vary substantially (approximately 25%) depending on which assay is used. Serum and plasma measurements are concordant. CgA is elevated in approximately 90% of gut NETs and correlates with tumor burden and recurrence. Highest values are noted in ileal NETs and gastrointestinal NETs associated with multiple endocrine neoplasia type 1. Both functioning and nonfunctioning pancreatic NETs have elevated values. CgA is more frequently elevated in well-differentiated tumors compared to poorly differentiated NETs. Effective treatment is often associated with decrease in CgA levels. Proton pump inhibitors falsely increase CgA, but levels normalize with therapy cessation.

CONCLUSIONS

CgA is currently the best available biomarker for the diagnosis of NETs. It is critical to establish diagnosis and has some utility in predicting disease recurrence, outcome, and efficacy of therapy. Measurement of plasma CgA is mandatory for the effective diagnosis and management of NET disease.

Distribution of obestatin and ghrelin in human tissues: immunoreactive cells in the gastrointestinal tract, pancreas, and mammary glands

Obestatin and ghrelin are two peptides derived from the same prohormone. It is well established that ghrelin is produced by endocrine cells in the gastric mucosa. However, the distribution of human obestatin immunoreactive cells is not thoroughly characterized. A polyclonal antibody that specifically recognizes human obestatin was produced. Using this antibody and a commercial antibody vs ghrelin, the distribution of obestatin and ghrelin immunoreactive cells was determined in a panel of human tissues using immunohistochemistry. The two peptides were detected in the mucosa of the gastrointestinal tract, from cardia to ileum, and in the pancreatic islets. Interestingly, epithelial cells in the ducts of mammary glands showed distinct immunoreactivity for both ghrelin and obestatin. By double immunofluorescence microscopy, it was shown that all detected cells were immunoreactive for both peptides. Furthermore, the subcellular localization of obestatin and ghrelin was essentially identical, indicating that obestatin and ghrelin are stored in the same secretory vesicles.

Malignant gastric ghrelinoma with hyperghrelinemia

A characteristic feature of neuroendocrine tumors is production and release of peptide hormone. Ghrelin is a 28-amino acid hormone that stimulates GH release. In this paper, we describe a patient with a metastasizing gastric neuroendocrine tumor displaying intense immunoreactivity for ghrelin and extremely high circulating levels of ghrelin. Tumor tissue biopsies from the primary tumor and one liver metastasis were examined by immunohistochemistry. Ghrelin and several other hormones and tumor markers were measured in blood. The clinical course of the patient was followed. Tumor tissue biopsies showed immunoreactivity for cytokeratin, chromogranin A, human synaptic vesicle protein 2, synaptophysin, and ghrelin. Grossly elevated circulating levels of total ghrelin, 2100 microg/liter (reference interval < 5 microg/liter) and active ghrelin, 28 microg/liter (reference interval < 0.1 microg/liter) were found at presentation. Chromogranin A, chromogranin B, and calcitonin levels were also increased. Both total and active ghrelin increased, despite treatment, during follow-up of the patient. We have identified and characterized a patient with a malignant gastric neuroendocrine tumor secreting ghrelin as the main hormone. This might be a new tumor entity of the stomach, and it is suggested that patients with malignant gastric neuroendocrine tumors should be investigated for ghrelin production.

Metastatic type 1 gastric carcinoid: A real threat or just a myth?

AIM: To describe disease characteristics and treatment modalities in a group of rare patients with metastatic gastric carcinoid type 1 (GCA1).

METHODS: Information on clinical, biochemical, radiological, histopathological findings, the extent of the disease, as well as the use of different therapeutic modalities and the long-term outcome were recorded. Patients’ data were assessed at presentation, and thereafter at 6 to 12 monthly intervals both clinically and biochemically, but also endoscopically and histopathologically. Patients were evaluated for the presence of specific symptoms; the presence of autoimmune disorders and the presence of other gastrointestinal malignancies in other family members were also recorded. The evaluation of response to treatment was defined using established WHO criteria.

RESULTS: We studied twenty consecutive patients with a mean age of 55.1 years. The mean follow-up period was 83 mo. Twelve patients had regional lymph node metastases and 8 patients had liver metastases. The primary tumor mean diameter was 20.13 ± 10.83 mm (mean ± SD). The mean Ki-67 index was 6.8% ± 11.2%. All but one patient underwent endoscopic or surgical excision of the tumor. The disease was stable in all but 3 patients who had progressive liver disease. All patients remained alive during the follow-up period.

CONCLUSION: Metastatic GCA1 carries a good overall prognosis, being related to a tumor size of ≥ 1 cm, an elevated Ki-67 index and high serum gastrin levels.

Incremental benefit of preoperative EUS for the detection of pancreatic neuroendocrine tumors: a meta-analysis

BACKGROUND

Current guidelines recommend CT scan or magnetic resonance imaging as the initial imaging modalities for the work-up of suspected pancreatic neuroendocrine tumors (PNETs).

OBJECTIVE

To determine the incremental benefit of preoperative EUS (IBEUS) for the detection of suspected PNETs after other investigative modalities have been attempted.

DESIGN

This systematic review searched MEDLINE, EMBASE, bibliographies of included articles, and conference proceedings for studies reporting original data regarding the preoperative detection of PNETs. Pooled IBEUS was calculated by using random effects models. Heterogeneity was explored by using stratified meta-analysis and meta-regression. Evidence of small-study effects was assessed by using funnel plots and the Begg test.

PATIENTS

Patients with suspected PNETs.

INTERVENTIONS

EUS evaluation.

MAIN OUTCOME MEASUREMENTS

The pooled IBEUS for the detection of PNETs after CT scan, with or without additional investigative modalities.

RESULTS

Among 4505 citations identified, we included 17 cohort studies (612 patients). EUS identified PNETs in 97% of cases. Improved PNET identification with EUS was observed in all of the studies. After adjusting for small-study effects, meta-analysis showed that EUS alone could identify PNETs in approximately 1 in 4 patients (adjusted IBEUS 26%; 95% confidence interval, 17%-37%). The pooled IBEUS varied based on the study design, study size, type of CT scan used, and the number of modalities used prior to EUS.

LIMITATIONS

The majority of included studies were retrospective. Small-study effects were observed.

CONCLUSION

Preoperative EUS is associated with an increase in PNET detection after other modalities are attempted.

Olfactory receptor 51E1 as a novel target for diagnosis in somatostatin receptor-negative lung carcinoids

Somatostatin receptors (SSTRs) may be used in lung carcinoids (LCs) for diagnosis and therapy, although additional targets are clearly warranted. This study aimed to investigate whether olfactory receptor 51E1 (OR51E1) may be a potential target for LCs. OR51E1 coding sequence was analyzed in LC cell lines, NCI-H727 and NCI-H720. OR51E1 transcript expression was investigated in LC cell lines and frozen specimens by quantitative real-time PCR. OR51E1, SSTR2, SSTR3, and SSTR5 expression was evaluated by immunohistochemistry on paraffin-embedded sections of 73 typical carcinoids (TCs), 14 atypical carcinoids (ACs), and 11 regional/distant metastases and compared with OctreoScan data. Immunohistochemistry results were rendered semiquantitatively on a scale from 0 to 3, taking into account the cellular compartmentalization (membrane vs cytoplasm) and the percentage of tumor cells (<50 vs >50%). Our results showed that WT OR51E1 transcript was expressed in both LC cell lines. OR51E1 mRNA was expressed in 9 out of 12 TCs and 7 out of 9 ACs (P=NS). Immunohistochemically, OR51E1, SSTR2, SSTR3, and SSTR5 were detected in 85, 71, 25, and 39% of TCs and in 86, 79, 43, and 36% of ACs respectively. OR51E1 immunohistochemical scores were higher or equal than those of SSTRs' in 79% of TCs and 86% of ACs. Furthermore, in the LC cases where all SSTR subtypes were lacking, membrane OR51E1 expression was detected in 10 out of 17 TCs and 1 out of 2 ACs. Moreover, higher OR51E1 immunohistochemical scores were detected in 5 out of 6 OctreoScan-negative LC lesions. Therefore, the high expression of OR51E1 in LCs makes it a potential novel diagnostic target in SSTR-negative tumors.

Expression of Somatostatin Receptors 1-5 and Dopamine Receptor 2 in Lung Carcinoids: Implications for a Therapeutic Role

OBJECTIVE

The expression of somatostatin receptors (SSTRs) and dopamine receptor 2 (DR2) in neuroendocrine tumors is of clinical importance as somatostatin analogues and dopamine agonists can be used for their localization and/or treatment. The objective of this study is to examine the expression of the five SSTR subtypes and DR2 in lung carcinoids (LCs).

METHODS

We conducted a retrospective study of 119 LCs from 106 patients [typical carcinoids (TCs): n = 100, and atypical carcinoids (ACs): n = 19]. The expression of all five SSTR subtypes and DR2 was evaluated immunohistochemically and correlated to clinicopathological data. In a subgroup of cases, receptor expression was further analyzed using semiquantitative RT-PCR.

RESULTS

SSTR2A was the SSTR subtype most frequently expressed immunohistochemically (72%), followed by SSTR1 (63%), SSTR5 (40%), and SSTR3 (20%), whereas SSTR4 was negative. DR2 was expressed in 74% and co-expressed with SSTR1 in 56%, with SSTR2A in 59%, with SSTR3 in 19%, and with SSTR5 in 37% of the tumors. Receptor expression was not related to the histological subtype, tumor aggressiveness (disease extent/grading) or functionality; however, DR2 was expressed more frequently in ACs than TCs (95 vs. 70%, p = 0.017). In a subset of patients, RT-PCR findings highly suggested that the expression of SSTR2A, SSTR3, DR2, and to a lesser extent that of SSTR1 and SSTR5 is the outcome of increased gene transcription.

CONCLUSIONS

The high and variable immunohistochemical expression of the majority of SSTRs along with their co-expression with DR2 in LCs provides a rationale for their possible treatment with agents that target these receptors.

Somatostatin and dopamine receptor expression in neuroendocrine neoplasms: correlation of immunohistochemical findings with somatostatin receptor scintigraphy visual scores

CONTEXT

The expression of somatostatin (sstr1-5) and dopamine (DR) receptors in neuroendocrine neoplasms (NENs) facilitates diagnosis by tumour visualization with somatostatin receptor scintigraphy (SRS) and directs towards specific treatment with peptide receptor radionuclide therapy (PRRT) with radiolabelled somatostatin analogues.

OBJECTIVE

To investigate the co-expression of sstrs, D2R in relation to pre-operative SRSs in NENs.

DESIGN

Prospective two-centre study.

PATIENTS AND MEASUREMENTS

We analysed pre-operative SRS of 60 patients [44 with gastrointestinal (GI) NENs and 16 with lung NENs] and compared SRS results with immunohistochemical (IHC) reactivity for sstr2, sstr3, sstr5 in sample tissues from primary (n = 54) and metastatic (n = 27) lesions and IHC reactivity for D2R in 23 samples from primary GI-NENs lesions.

RESULTS

Sstr2 was the commonest sstr expressed (65·4%) and was co-expressed with sstr3 and sstr5 in 32·1% and 24·7% of the specimens, respectively. In 67 of 81 specimens (82·7%), there was concordance of sstr2 immunohistochemistry with SRS findings (P < 0·001). D2R was expressed in only 8 of 23 (34·8%) GI-NENs while was co-expressed with sstr2 in all cases. SRS grade, as per Krenning scale, was higher in metastatic foci, large-size (>2 cm) tumours and GI-NENs, whereas sstr2 intensity was greater in GI compared to lung NENs. SRS grade showed higher correlation with sstr2 (r = 0·6, P < 0·001) and D2R (r = 0·5, P < 0·001) IHC intensity scores than tumour size (r = 0·4, P < 0·001) and sstr3 (r = 0·4, P < 0·001) intensity score.

CONCLUSIONS

Sstr2 IHC expression and SRS are useful tools for the diagnosis and management of NENs because they display a high concordance. IHC expression of DR2 seems to be of potential clinical significance in GI-NENs tumours.

Endogenous estrogen exposure in relation to distribution of histological type and estrogen receptors in gastric adenocarcinoma

BACKGROUND

Estrogen might protect women against gastric adenocarcinoma of the intestinal histological type. We addressed this hypothesis and proposed that gastric estrogen receptors (ERs) are involved.

METHODS

A population-based cohort of patients with gastric adenocarcinoma diagnosed in 1958-2004 in the county of Stockholm was identified through the Swedish Cancer Register. The patients were categorized regarding their endogenous estrogen exposure at diagnosis into: women aged less than 50 years, labelled "exposed women" (n=364), men aged less than 50 years, labelled "unexposed men" (n=396), and women aged more than 70 years, labelled "unexposed women" (n=3008). Tumor specimens were reviewed, and 289 cases were classified into intestinal (n=101) or diffuse type (n=188). Cases of intestinal adenocarcinomas (n=45) were tested for presence of ERalpha, ERbeta, and ERbeta cx by immunohistochemistry.

RESULTS

Compared to "exposed women", the intestinal type of gastric adenocarcinoma was more than four times more common among "unexposed men" (odds ratio [OR], 4.7; 95% confidence interval [CI], 2.2-10.3) and nine times more common among "unexposed women" (OR, 9.1; 95% CI, 4.3-19.6). No differences in ER expression were found. A comparison of ERs in tissues taken from the tumors and adjacent gastric mucosa revealed a loss of ERbeta and a gain of ERalpha in the tumor cells. The presence of ERbeta cx was identified for the first time in gastric tumors.

CONCLUSION

Gastric adenocarcinoma of the intestinal type is less common in women with high endogenous estrogen exposure, indicating a preventive effect of estrogen. No differences in the distribution of ERs was found between the three estrogen exposure groups. The presence of ERbeta cx in gastric cancer warrants further investigation.

Differentiated expression of somatostatin receptor subtypes in experimental models and clinical neuroblastoma

BACKGROUND

Neuroblastoma (NB) is a solid tumor of childhood originating from the adrenal medulla or sympathetic nervous system. Somatostatin (SS) is an important regulator of neural and neuroendocrine function, its actions being mediated through five specific membrane receptors. The aim of this study was to investigate the expression of the different somatostatin receptors (SSTRs) in NB tumor cells that may form targets for future therapeutic development.

PROCEDURE

Tumor specimens from 11 children with stage II-IV disease were collected before and/or after chemotherapy. Experimental tumors derived from five human NB cell lines were grown subcutaneously in nude mice. Expression of SSRTs, the neuroendocrine marker chromogranin A (CgA) and SS was detected by immunohistochemistry using specific antibodies.

RESULTS

SSTR2 was detected in 90%, SSTR5 in 79%, SSTR1 in 74%, SSTR3 in 68% whereas SSTR4 was expressed in 21% of the clinical tumors. The experimental tumors expressed SSTRs in a high but variable frequency. All clinical tumors showed immunoreactivity for CgA but not for SS.

CONCLUSION

The frequent expression of SSTRs indicates that treatment with unlabeled or radiolabeled SS analogs should be further explored in NB.

Gastric neuroendocrine neoplasms type 1: A systematic review and meta-analysis

BACKGROUND

To date, the histopathological parameters predicting the risk of lymph node (LN) metastases and local recurrence, associated mortality and appropriateness of endoscopic or surgical resection in patients with gastric neuroendocrine neoplasms type 1 (GNENs1) have not been fully elucidated.

AIM

To determine the rate of LN metastases and its impact in survival in patients with GNEN1 in relation to certain clinico-pathological parameters.

METHODS

The PubMed, EMBASE, Cochrane Library, Web of Science and Scopus databases were searched through January 2019. The quality of the included studies and risk of bias were assessed using the Newcastle-Ottawa Scale (NOS) in accordance with the Cochrane guidelines. A random effects model and pooled odds ratios (OR) with 95%CI were applied for the quantitative meta-analysis.

RESULTS

We screened 2933 articles. Thirteen studies with 769 unique patients with GNEN1 were included. Overall, the rate of metastasis to locoregional LNs was 3.3% (25/769). The rate of LN metastases with a cut-off size of 10 mm was 15.3% for lesions > 10 mm (vs 0.8% for lesions < 10 mm) with a random-effects OR of 10.5 (95%CI: 1.4 -80.8; heterogeneity: P = 0.126; I² = 47.5%). Invasion of the muscularis propria was identified as a predictor for LN metastases (OR: 17.2; 95%CI: 1.8-161.1; heterogeneity: P = 0.165; I² = 44.5%), whereas grade was not clearly associated with LN metastases (OR: 2; 95%CI: 0.3-11.6; heterogeneity: P = 0.304; I² = 17.4%). With regard to GNEN1 local recurrence, scarce data were available. The 5-year disease-specific survival for patients with and without LN metastases was 100% in most available studies irrespective of the type of intervention. Surgical resection was linked to a lower risk of recurrence (OR: 0.3; 95%CI: 0.1-1.1; heterogeneity: P = 0.173; I² = 31.9%). The reported complication rates of endoscopic and surgical intervention were 0.6 and 3.8%, respectively.

CONCLUSION

This meta-analysis confirms that tumor size ≥ 10 mm and invasion of the muscularis propria are linked to a higher risk of LN metastases in patients with GNEN1. Overall, the metastatic propensity of GNEN1 is low with favorable 5-year disease-specific survival rates reported; hence, no clear evidence of the prognostic value of LN positivity is available. Additionally, there is a lack of evidence supporting the prediction of local recurrence in GNEN1, even if surgery was more often a definitive treatment.

Obestatin/ghrelin cells in normal mucosa and endocrine tumours of the stomach

OBJECTIVE

Obestatin and ghrelin are derived from the same gene and co-expressed in the same endocrine cells. Vesicular monoamine transporter-2 (VMAT-2), a marker for enterochromaffin-like (ECL) cells, is considered to be expressed in ghrelin cells. The aim was to establish if the two peptides and the transporter are co-expressed, both in normal gastric mucosa and in gastric endocrine tumours.

DESIGN

An immunohistochemical study was performed on gastric biopsy material and on surgical specimens from 63 patients with gastric endocrine tumours and from individuals with normal gastric mucosa. Cells displaying obestatin immunoreactivity were examined regarding co-localization with ghrelin and VMAT-2. Both single- and double-immunostaining techniques were applied. Obestatin concentration in blood was measured in a subgroup of these patients. The results were correlated to various clinico-pathological parameters.

RESULTS

In the normal mucosa, obestatin/ghrelin-immunoreactive cells rarely co-expressed VMAT-2. In most tumour tissue specimens, only a fraction of neoplastic cells displayed immunoreactivity to obestatin, and these cells always co-expressed ghrelin. Neoplastic obestatin-/ghrelin-IR cells invariably expressed VMAT-2, except for two ghrelinomas. The obestatin concentrations in blood were consistently low and did not correlate to clinico-pathological data.

CONCLUSIONS

Obestatin and ghrelin immunoreactivity always occurred in the same endocrine cells in the gastric mucosa but these cells only occasionally co-expressed VMAT-2, opposite to the findings in tumours. These results indicate that endocrine cells expressing obestatin and ghrelin mainly differ from VMAT-2 expressing cells (ECL-cells) and can develop into pure ghrelinomas. Plasma concentrations of obestatin did not correlate to cellular expression.

Connective tissue growth factor expression in endocrine tumors is associated with high stromal expression of alpha-smooth muscle actin

OBJECTIVE

Complications due to fibrosis development are common in patients with well-differentiated endocrine carcinomas in the small intestine (ileal carcinoids). Connective tissue growth factor (CTGF) expression in ileal carcinoids may be related to this fibrosis development. This study aimed to examine CTGF expression in relation to local myofibroblast differentiation in a large series of ileal carcinoids and in different types of endocrine tumors.

METHODS

Immunoreactivity (IR) for CTGF and α-smooth muscle actin (α-SMA), a marker for myofibroblasts, was compared in serial tumor tissue sections from 42 patients with ileal carcinoids and from 80 patients with other endocrine tumors. Western blot was performed on an additional 21 patients with ileal carcinoids.

RESULTS

CTGF IR was present in >50% of tumor cells in all 42 ileal carcinoids and in 2 out of 14 endocrine pancreatic tumors, 4 out of 6 rectal carcinoids, and 1 out of 5 lung carcinoids. Tumors with abundant CTGF expression also displayed α-SMA IR in stromal fibroblast-like cells, whereas other endocrine tumors displayed less or no CTGF and α-SMA IR. Protein bands corresponding to full-length CTGF (36-42 kDa) were detected in protein lysates from ileal carcinoids.

CONCLUSION

CTGF is uniquely prevalent in ileal carcinoids when compared with most other endocrine tumor types. Immunoreactive cells are adjacent areas with increased fibrovascular stroma that express α-SMA. This supports a potential role for CTGF in myofibroblast-mediated fibrosis associated with ileal carcinoids, and indicates that CTGF should be investigated as a target for future therapy.

Ghrelin immunoreactive cells in gastric endocrine tumors and their relation to plasma ghrelin concentration

GOALS

Our aim was to elucidate the incidence and distribution pattern of ghrelin-immunoreactive (IR) cells in various types of human gastric endocrine tumors, and their surrounding mucosa, and relate the findings to total ghrelin concentrations in plasma.

BACKGROUND

It has been demonstrated previously, that ghrelin-IR cells are present not only in normal human gastric oxyntic mucosa, but also in all types of enterochromaffinlike (ECL) cell carcinoids (ECL-CCs), and in mucosal regions affected by ECL cell hyperplasia.

STUDY

Forty-eight gastric endocrine tumors were included in the study: 32 type I ECL-CCs, 3 type II, 9 type III, 1 non-ECL-CC, and 3 poorly differentiated endocrine carcinomas. The tumors were analyzed immunohistochemically with antibodies raised versus chromogranin A, synaptophysin, serotonin, somatostatin, vesicular monoamine transporter 2 and ghrelin. Total ghrelin in plasma was measured in 20 patients, using a commercial radioimmunoassay kit.

RESULTS

Ghrelin-IR cells were found in all types I and II ECL-CCs but in only a few cases of the other tumors. Ghrelin-IR cells were also found among the hyperplastic endocrine cells in the mucosa surrounding types I and II, where they showed diffuse, linear, nodular and adenomatoid hyperplasia patterns. In type III ECL-CCs and poorly differentiated endocrine carcinomas, only diffuse and linear ghrelin-IR cell hyperplasia was present in the oxyntic mucosa in about half of the cases, whereas the mucosa of the non-ECL-CC did not show this feature.

CONCLUSIONS

Despite the frequent occurrence of ghrelin-IR cells in both the neoplastic parenchyma and the oxyntic mucosa, plasma total ghrelin concentrations remained within the reference range and can therefore not be used as a clinical marker to identify ghrelin expressing ECL-CCs or ghrelin cell hyperplasia.

Current concepts in the diagnosis and management of type 1 gastric neuroendocrine neoplasms

The vast majority of gastrin-related gastrointestinal neuroendocrine neoplasms (GI-NENs) develop in the context of chronic atrophic gastritis (type 1), a condition closely related to autoimmune thyroid diseases. These neoplasms are defined as gastric NENs type 1 (GNEN1) and have recently been shown to constitute the commonest GI-NENs in a prospective study. GNEN1s are usually multiple and follow a relative indolent course, raising questions regarding the extent that such patients should be investigated and the appropriate therapeutic interventions needed. Recently, a number of consensus statements and guidelines have been published from various societies dealing with the diagnosis and management of GI-NENs. Endocrinologists are among the many different medical specialties involved in GNEN1s diagnosis and management. However, despite recent advances, few randomized trials are available, and thus existing evidence remains relatively weak compared to other malignancies. The purpose of this review is to provide recent evidence along with currently employed modalities addressing the diagnosis, management, long-term follow-up and potential comorbidities of GNEN1s.

Unusual complication of a pancreatic neuroendocrine tumor presenting with malignant hypercalcemia

CONTEXT

Hypersecretion of PTHrP is a relatively common cause of malignancy-related hypercalcemia but has only been described in a few cases of neuroendocrine tumors (NET).

OBJECTIVE

The aim of this case report is to describe the clinical syndrome, complex therapeutic interventions, and unusual complications caused by persistent PTHrP hypersecretion in a patient with a pancreatic NET.

CASE ILLUSTRATION

A 58-yr-old male patient presented with nonspecific abdominal pain and was found to have severe hypercalcemia secondary to a well-differentiated NET of the pancreas associated with extensive liver metastases. Elevated ionized calcium levels accompanied by low serum PTH and remarkably elevated PTHrP concentrations were consistent with PTHrP-related hypercalcemia that proved to be resistant to various chemotherapeutic regimens and supportive therapy. Partial control of the humoral syndrome was obtained only after the application of cytoreductive interventions and the introduction of various molecular targeted therapies. Due to persistent PTHrP action, bone disease emerged in the form of brown tumors.

DISCUSSION

The manifestation of paraneoplastic syndrome due to PTHrP hypersecretion, despite its rareness in NET, should be considered in the differential diagnosis of hypercalcemia in such tumors. Moreover, the appearance of bone lesions in this setting may be in the context of metabolic bone disease and could be misdiagnosed as bone metastases.

Gastric carcinoid in a patient infected with Helicobacter pylori: A new entity?

There are four types of gastric carcinoid tumors, classified according to their histology and malignant potential. Only a few cases of carcinoid tumors in patients infected with Helicobacter pylori (H. pylori) have been reported so far. We report a patient infected with H. pylori presenting with a small solitary gastric carcinoid tumor with very low proliferative rate and normal gastrin levels. The tumor was endoscopically removed and the patient received an eradication therapy against H. pylori. No signs of metastatic disease have been found so far during more than 3 year of follow-up. Infection with H. pylori may cause chronic gastritis with normal or elevated gastrin levels, leading to the development of gastric carcinoids by mechanisms unrelated to gastrin. Enterochromaffin-like cell tumors related to a chronic H. pylori infection may be considered as a distinct type of gastric carcinoid tumors.

Chronic pancreatitis and the heart disease: Still terra incognita?

BACKGROUND

It has been suggested that chronic pancreatitis (CP) may be an independent risk factor for development of cardiovascular disease (CVD). At the same time, it seems that congestive heart failure (CHF) and CP share the responsibility for the development of important clinical conditions such as sarcopenia, cachexia and malnutrition due to development of cardiac cachexia and pancreatic exocrine insufficiency (PEI), respectively.

AIM

To explore the evidence regarding the association of CP and heart disease, more specifically CVD and CHF.

METHODS

A systematic search of MEDLINE, Web of Science and Google Scholar was performed by two independent investigators to identify eligible studies where the connection between CP and CVD was investigated. The search was limited to articles in the English language. The last search was run on the 1st of May 2019. The primary outcomes were: (1) Incidence of cardiovascular event [acute coronary syndrome (ACS), chronic coronary disease, peripheral arterial lesions] in patients with established CP; and (2) Incidence of PEI in patients with CHF.

RESULTS

Out of 1166 studies, only 8 were eligible for this review. Studies regarding PEI and CHF showed an important incidence of PEI as well as associated malabsorption of nutritional markers (vitamin D, selenium, phosphorus, zinc, folic acid, and prealbumin) in patients with CHF. However, after substitution of pancreatic enzymes, it seems that, at least, loss of appetite was attenuated. On the other side, studies investigating cardiovascular events in patients with CP showed that, in CP cohort, there was a 2.5-fold higher incidence of ACS. In another study, patients with alcohol–induced CP with concomitant type 3c diabetes had statistically significant higher incidence of carotid atherosclerotic plaques in comparison to patients with diabetes mellitus of other etiologies. Earlier studies demonstrated a marked correlation between the clinical symptoms in CP and chronic coronary insufficiency. Also, statistically significant higher incidence of arterial lesions was found in patients with CP compared to the control group with the same risk factors for atherosclerosis (hypertension, smoking, dyslipidemia). Moreover, one recent study showed that PEI is significantly associated with the risk of cardiovascular events in patients with CP.

CONCLUSION

Current evidence implicates a possible association between PEI and malnutrition in patients with CHF. Chronic pancreatic tissue hypoxic injury driven by prolonged splanchnic hypoperfusion is likely to contribute to malnutrition and cachexia in patients with CHF. On the other hand, CP and PEI seem to be an independent risk factor associated with an increased risk of cardiovascular events.

Endocrine paraneoplastic syndromes in patients with neuroendocrine neoplasms

OBJECTIVE

Our aim was to assess the prevalence of endocrine paraneoplastic syndromes (EPNS) in neuroendocrine neoplasms (NENs) and estimate its impact on patient outcomes.

DESIGN

This is a retrospective analysis of 834 patients with NENs (611 gastrointestinal, 166 thoracic, 57 of unknown and various other primary origin). We included 719 consecutive NEN patients treated at EKPA-Laiko Hospital, Athens, Greece and 115 patients with lung carcinoid (LC) treated at Uppsala University Hospital, Uppsala, Sweden. EPNS diagnosis was based on standard criteria.

METHODS

Twenty-one patients with EPNS were detected: 16 with ectopic Cushing's syndrome (ECS), one with hypercalcaemia due to parathyroid hormone-related protein (PTHrP) secretion, three with hypercalcitonaemia and one patient with dual secretion of calcitonin and beta-human chorionic gonadotropin (β-HCG). All tumours were well-differentiated; 10 patients had Stage IV disease at diagnosis.

RESULTS

The prevalence of EPNS in the Greek cohort was 1.9%, whereas that of ECS among LC patients in both centres was 6.7%. Median overall survival (OS) for patients with EPNS was 160.7 months (95%CI, 86-235.4) and median event-free survival (EFS) was 25.9 months (95%CI, 0-57.2). Patients presenting with EPNS prior to NEN diagnosis had longer EFS compared to patients with synchronous or metachronous EPNS (log-rank P = 0.013). Patients with ECS of extra-thoracic origin demonstrated shorter OS and EFS compared to patients with ECS of lung or thymic origin (log-rank P = 0.001 and P < 0.001, respectively). LC patients with and without ECS were comparable in 5-year and 10-year OS rates (66.7% and 33.3% versus 89.8% and 60.2%, respectively; 95%CI [189.6-300.4 months], log-rank P = 0.94) and in median EFS, 67 versus 183 months, 95%CI [50.5-207.5], log-rank P = 0.12).

CONCLUSION

EPNS are relatively rare in patients with NENs and mainly concern well-differentiated tumours of the foregut. Among patients with EPNS, LC-related ECS may not adversely affect patient outcomes when diagnosed prior to NEN and effectively been treated.

Expression of connective tissue growth factor and IGF1 in normal and neoplastic gastrointestinal neuroendocrine cells and their clinico-pathological significance

Connective tissue growth factor (CTGF) and IGF1 are both expressed in a variety of tumours and are involved in tumourigenesis. However, information about their expression in the gastrointestinal (GI) neuroendocrine (NE) cells and tumours is mainly limited, with the exception of midgut carcinoids where abundant CTGF expression has been demonstrated. Normal mucosa specimens from stomach and ileum, as well as tumour tissue specimens from gastric NE tumours (GNETs; n=58) and midgut NETs (n=38) were included. Immunohistochemical techniques were used to investigate the possible expression of CTGF and IGF1 in GI NE cells and tumours. The latter results were correlated with various clinico-biochemical and histopathological variables. CTGF was expressed in a proportion of NE cells of the normal GI mucosa but not in enterochromaffin-like (ECL) cells, whereas IGF1 was undetectable. CTGF was absent in the foci of ECL cell hyperplasia, and in most of the poorly differentiated carcinomas, but present in some GNETs (mainly in type III ECL cell carcinoids (ECL-CCs)) and in all but one midgut NETs. CTGF correlated with tumour stage in well-differentiated GNETs and with size larger than 1  cm but only in the subgroup of type I ECL-CCs. IGF1 was detected in the foci of ECL cell hyperplasia and in all GI NETs. These findings suggest that both CTGF and IGF1 may be involved in the neoplastic transformation of GI NE cells, whereas IGF1 may play an important role even at early stage.

Predictive value of gastrin levels for the diagnosis of gastric enterochromaffin-like cell hyperplasia in patients with Hashimoto's thyroiditis

AIM

Gastrin and chromogranin A (CgA) levels have been tested for the diagnosis of enterochromaffin-like cell hyperplasia (ECLH) in patients with type 1 diabetes and autoimmune atrophic gastritis but not for patients with Hashimoto's thyroiditis (HT). The aim of the study was to develop receiver operating characteristic (ROC) curves for gastrin and CgA levels and other clinical and biochemical parameters, as means for pretest probability of gastric ECLH in patients with HT.

METHODS

A total of 115 patients with HT were prospectively studied for a median period of 4 (2-7) years. Gastrin, CgA, vitamin B12, anti-parietal cell antibodies, free thyroxine, thyrotropin, and neuron-specific enolase levels were measured. Their predictive values were calculated according to the histological findings for ECLH diagnosis from esophagogastroduodenoscopy-obtained biopsies.

RESULTS

Thirteen patients (11.3%) had ECLH. The areas under the curve for gastrin and CgA level were 0.898 (p < 0.001) and 0.853 (p < 0.001), respectively. The product sensitivity × specificity was 0.803 and 0.653 for gastrin and CgA levels >89.5 and >89.1 ng/ml, respectively. Two and 4 patients with ECLH had normal gastrin and CgA levels, respectively. The most specific combined parameters predicting ECLH were gastrin >89.5 ng/ml with concomitant low B12 levels (96.1% specificity).

CONCLUSION

Gastrin levels have high diagnostic accuracy for ECLH identification in patients with HT, and are highly specific when combined with low B12 levels. However, they should be interpreted with caution, as some patients may harbor gastric ECLH even if gastrin levels are not increased, necessitating further follow-up.

Increased autophagy/mitophagy levels in primary tumours of patients with pancreatic neuroendocrine neoplasms

BACKGROUND/AIMS

We assessed the levels of autophagy and mitophagy, that are linked to cancer development and drug resistance, in well differentiated pancreatic neuroendocrine neoplasms (PanNENs) and correlated them with clinico-pathological parameters.

METHODS

Fluorescent immunostaining for the autophagy markers LC3Β and p62/or LAMP1 was performed on 22 PanNENs and 11 controls of normal pancreatic tissues and validated through Western blotting. Autophagy quantitative scoring was generated for LC3B-positive puncta and analysed in relation to clinico-pathological parameters. TOMM20/LC3B qualitative assessment of mitophagy levels was undertaken by fluorescent immunostaining. The presence of autophagy/mitophagy was validated by transmission electron microscopy.

RESULTS

Autophagy levels (LC3B-positive puncta/cell) were discriminative for normal vs. NEN pancreatic tissue (p = 0.007). A significant association was observed between autophagy levels and tumour grade (Ki67 < 3% vs. Ki67 ≥ 3%; p = 0.021), but not functionality (p = 0.266) size (cut-off of 20 mm; p = 0.808), local invasion (p = 0.481), lymph node- (p = 0.849) and distant metastases (p = 0.699). Qualitative assessment of TOMM20/LC3B demonstrated strong mitophagy levels in PanNENs by fluorescent immunostaining as compared with normal tissue. Transmission electron microscopy revealed enhanced autophagy and mitophagy in PanNEN tissue. Response to molecular targeted therapies in metastatic cases (n = 4) did not reveal any patterns of association to autophagy levels.

CONCLUSIONS

Increased autophagy levels are present in primary tumours of patients with PanNENs and are partially attributed to upregulated mitophagy. Grade was the only clinico-pathological parameter associated with autophagy scores.

Expression of the coiled coil domain containing protein 116 in the pancreatic islets and endocrine pancreatic tumors

AIMS

Coiled coil domain containing protein 116 (CCDC116) is a product of the gene coiled coil domain containing 116 located on human chromosome 22. Its function has not yet been established. The present study focuses on the expression of this protein in human pancreatic islets and in the endocrine pancreatic tumors (EPTs).

METHODS AND RESULTS

Expression of the protein was evaluated by immunohistochemistry in endocrine pancreas from six patients and in various EPTs from 51 patients. In pancreatic islets, virtually all insulin, approx. 75% of the somatostatin, and approx. 60% of the pancreatic polypeptide (PP) cells were immunoreactive for the CCDC116 protein whereas glucagon, ghrelin and the exocrine cells were not. All insulinomas, gastrinomas, non-functioning sporadic tumors and the hereditary multihormonal EPTs were immunoreactive with variable relative incidence. Two of the three somatostatinomas, and one of the three ACTH-secreting tumors also expressed CCDC116.

CONCLUSIONS

The CCDC116 protein is expressed in all islet cell types except the glucagon and ghrelin cells. Most of the EPTs also contained CCDC116 protein. These findings suggest that this protein may play some role for the above mentioned endocrine cells and tumors. Its function has to be investigated in future studies.

Lung Carcinoids: Long-Term Surgical Results and the Lack of Prognostic Value of Somatostatin Receptors and Other Novel Immunohistochemical Markers

BACKGROUND/AIMS

Lung carcinoids (LCs) are often diagnosed at an early stage and surgical intervention becomes the next phase of treatment. To date, there is lack of long-term follow-up data after surgery and prognostication based on WHO classification criteria and evolving prognostic markers, particularly the expression of somatostatin receptors (SSR).

METHODS

We included 102 consecutive patients (72 women; age at baseline 51 ± 16 years [mean ± SD]) with LCs, who underwent thoracic surgery (n = 99) and/or laser treatment (n = 8). Hospital charts were reviewed for clinico-pathological parameters. Immunohistochemical (IHC) expression of SSR1-5 and other novel markers were studied with regard to their prognostic value.

RESULTS

Five- and 10-year overall survival (OS) was 96 and 83% respectively; relative survival (RS) was 101 and 93% respectively; and event-free survival (EFS) was 80 and 67% respectively. Independent prognostic factors for OS, RS and/or EFS were age at diagnosis, histopathological type and the presence of ipsilateral mediastinal subcarinal lymph node metastases. Macro-radicality of resective surgery and its extent were associated with increased OS and EFS. The IHC expression of SSR1-5 and other novel markers was not associated with OS or EFS.

CONCLUSION

The long-term outcome of surgically treated patients with LCs is favourable. Age, histopathological type and ipsilateral mediastinal subcarinal lymph node status at baseline were independent prognostic factors for survival and disease recurrence or progression. The extent of surgery and operative macro-radicality also had an impact on prognosis. None of the IHC markers tested appeared to be associated with disease prognosis.

Magnetic Resonance Imaging or Endoscopic Ultrasonography for Detection and Surveillance of Pancreatic Neuroendocrine Neoplasms in Patients with Multiple Endocrine Neoplasia Type 1?

Our aim was to compare the clinical utility of Magnetic Resonance Imaging (MRI) and Endoscopic Ultrasonography (EUS) in identifying Pancreatic Neurondocrine Neoplasms (PanNENs) and monitoring size alterations in Multiple Endocrine Neoplasia type 1 (MEN1) patients. Thirty-one MEN1 patients with PanNENs and concurrent screening by EUS and abdominal MRI were included and 129 pancreatic lesions were detected in total. MRI detected fewer lesions than EUS (n=73 vs. 110, p=0.006). MRI sensitivity and specificity compared to EUS at 20 and 10 mm cut-offs of maximal lesion diameter were 96 and 88% (20 mm cut-off) and 90 and 82%(10 mm cut-off), respectively (concordance rates of 97 and 87% and Cohen's kappa=0.912 and 0.718, respectively). Lesions<1 cm were more often detected with EUS (p=0.025). Data from sequential concurrent imaging on lesion growth rate [n=7 (mean±SD: 2 mm/year±3.4 mm vs. 1.9 mm/year±3.6 mm)] over a period of at least two years as well as pathology data in connection to preoperative concurrent imaging were available in a small number of patients (n=7, p=0.933 for mean differences in maximal lesion diameter). MRI of the pancreas was more readily available and less expensive than EUS in an outpatient setting. In conclusion, MRI performs well compared to EUS for the detection and subsequent surveillance of MEN1-related panNENs larger than 10 mm and seems to be cost-effective. Both modalities could be used at initial assessment and MRI alone could be utilized thereafter in patient surveillance. EUS retains its value in surgical planning and the detection of small mostly functional PanNENs.