Chromogranin A as a marker for diagnosis, treatment, and survival in patients with gastroenteropancreatic neuroendocrine neoplasm

Predictive Factors of Response to Streptozotocin in Neuroendocrine Pancreatic Neoplasms

Pancreatic neuroendocrine neoplasms (Pan-NENs) may exhibit a heterogeneous clinical course, ranging from indolent to progressive/metastatic behavior. In the latter scenario, streptozocin (STZ) is considered the cornerstone of systemic treatment; however, response to STZ-based chemotherapy may vary among individuals. In this narrative review, we aimed to identify the predictive factors of response to STZ in advanced Pan-NENs. We performed an extensive search in international online databases for published studies and ongoing clinical trials evaluating STZ in Pan-NENs. We found 11 pertinent studies evaluating 17 patient-, tumor-, or treatment-related factors. Age, CgA blood levels, tumor grade, Ki-67% index, anatomical location of the primary tumor, tumor stage, site of metastasis origin, liver tumor burden, extrahepatic spread, functional status, O6-methylguanine-methyltransferase (MGMT) status, line of therapy, and response to previous treatments were all statistically associated with radiological response and/or survival. The identified predictors may help clinicians make appropriate treatment decisions, in this way improving clinical outcomes in patients with advanced Pan-NENs.

The hidden potential of glycomarkers: Glycosylation studies in the service of cancer diagnosis and treatment

Changes in the glycosylation process appear early in carcinogenesis and evolve with the growth and spread of cancer. The correlation of the characteristic glycosylation signature with the tumor stage and the appropriate therapy choice is an important issue in translational medicine. Oncologists also pay attention to extracellular vesicles as reservoirs of new cancer glycomarkers that can be potent for cancer diagnosis/prognosis. In this review, we recall glycomarkers used in oncology and show their new glycoforms of improved clinical relevance. We summarize current knowledge on the biological functions of glycoepitopes in cancer-derived extracellular vesicles and their potential use in clinical practice. Is glycomics a future of cancer diagnosis? It may be, but in combination with other omics analyses than alone.

Management of Small Nonfunctioning Pancreatic Neuroendocrine Neoplasms: Current Opinion and Controversies

The incidence of small and asymptomatic pancreatic neuroendocrine neoplasms (PNENs) has increased due to the widespread use of high-resolution diagnostic imaging in screening programs. Most PNENs are slow-growing indolent neoplasms. However, a local invasion or metastasis can sometimes occur with PNENs, leading to a poor prognosis. The management of small, nonfunctioning PNENs remains under debate. The National Comprehensive Cancer Network guidelines recommend observation in selected cases of small PNENs less than 2 cm. Pancreatic surgery remains a high-risk operation with a 28-30% morbidity and 1% mortality. Therefore, the decision on how to manage small PNENs is challenging. This review focuses on the management of small nonfunctioning PNENs. We also highlight the malignant potential of small PNENs according to tumor size, tumor grade, and tumor biomarker. Endoscopic-ultrasound-guided biopsy is recommended to evaluate the potential risk of malignancy. Furthermore, we discuss the current guidelines and future directions for the management of small PNENs.

Circulating Angiogenic Markers in Gastroenteropancreatic Neuroendocrine Neoplasms: A Systematic Review

Background: Neuroendocrine neoplasms are a heterogeneous group of tumors that raise challenges in terms of diagnosis, treatment and monitoring. Despite continuous efforts, no biomarker has showed satisfying accuracy in predicting outcome or response to treatment. Methods: We conducted a systematic review to determine relevant circulating biomarkers for angiogenesis in neuroendocrine tumors. We searched three databases (Pubmed, Embase, Web of Science) using the keywords “neuroendocrine” and “biomarkers”, plus specific biomarkers were searched by full and abbreviated name. From a total of 2448 publications, 11 articles met the eligibility criteria. Results: VEGF is the most potent and the most studied angiogenic molecule, but results were highly controversial. Placental growth factor, Angiopoietin 2 and IL-8 were the most consistent markers in predicting poor outcome and aggressive disease behavior. Conclusions: There is no robust evidence so far to sustain the use of angiogenic biomarkers in routine practice, although the results show promising leads.

Role of Chromogranin A in the Diagnosis and Follow-up of Neuroendocrine Tumors: Real-World Experience

OBJECTIVE

The aim of this study was to assess the utility of serum chromogranin A (CgA) along the clinical pathway of patients with neuroendocrine tumors (NETs).

METHODS

A retrospective review of medical records was conducted of patients with NET who had at least 1 measurement of CgA between January 2015 and April 2021 at a large metropolitan Australian hospital. Chromogranin A was classified as increased or decreased if there was at least a 25% change in sequential levels and was compared with disease response by anatomical or functional imaging if within 6 weeks (considered concurrent).

RESULTS

Of 102 patients with NETs, 67 had at least 1 serum CgA level: 50 had been ordered during diagnostic workup, of which 33 were elevated (sensitivity: 66%; 95% confidence interval, 51%-79%). Of 129 CgA results concurrent with imaging, the sensitivity for detecting progressive disease was 28% (95% confidence interval, 15%-44%).

CONCLUSIONS

Our findings support previous concerns that CgA adds little value in clinical decision-making.

Current updates and future directions in diagnosis and management of gastroenteropancreatic neuroendocrine neoplasms

Gastroenteropancreatic neuroendocrine neoplasms are a heterogenous group of rare neoplasms that are increasingly being discovered, often incidentally, throughout the gastrointestinal tract with varying degrees of activity and malignant potential. Confusing nomenclature has added to the complexity of managing these lesions. The term carcinoid tumor and embryonic classification have been replaced with gastroenteropancreatic neuroendocrine neoplasm, which includes gastrointestinal neuroendocrine and pancreatic neuroendocrine neoplasms. A comprehensive multidisciplinary approach is important for clinicians to diagnose, stage and manage these lesions. While histological diagnosis is the gold standard, recent advancements in endoscopy, conventional imaging, functional imaging, and serum biomarkers complement histology for tailoring specific treatment options. In light of developing technology, our review sets out to characterize diagnostic and therapeutic advancements for managing gastroenteropancreatic neuroendocrine tumors, including innovations in radiolabeled peptide imaging, circulating biomarkers, and endoscopic treatment approaches adapted to different locations throughout the gastrointestinal system.

Peptide receptor radionuclide therapy implementation and results in a predominantly gastrointestinal neuroendocrine tumor population: A two-year experience in a nonuniversity setting

Neuroendocrine tumors (NETs) are rare, but the incidence and prevalence of NETs are increasing in the United States. While surgery is the preferred treatment for NETs, it is not a viable option for metastatic disease. Lutathera (177Lu-DOTATATE) is approved by the United States Food and Drug Administration and the European Medicines Agency for the treatment of gastroenteropancreatic (GEP)-NETs in adults. There is limited information on GEP-NET treatment responses to Lutathera.Our institution launched a peptide receptor radionuclide therapy (PRRT) service line using Lutathera with involvement from a multidisciplinary team and complete collaboration between hospital administration and clinical providers. A prospective registry study was also established in order to collect patient demographics and clinical data regarding the treatment of GEP primary NETs with Lutathera.Between August 2018 and July 2020, 35 GEP-NET patients were treated with Lutathera, of which 65.71% received 4 complete cycles and 25.71% received 3 cycles; 5.71% and 2.86% received 2 and 1 cycles of PRRT, respectively. Most adverse events during the course of our study were low grade using the common terminology criteria for adverse events system. Of the patients who completed all 4 cycles: 22% showed partial response to Lutathera, 44% showed stable disease, and 13% showed disease progression based on a qualitative assessment of positron emission tomography/computed tomography imaging.From our experience, Lutathera was well tolerated in patients with GEP-NET. Additional studies are needed to examine long-term clinical and patient-reported outcomes associated with GEP-NET treatment as well as financial considerations for hospitals embarking on a PRRT program.

Chronic Autoimmune Gastritis: Modern Diagnostic Principles

This article summarizes and systematizes the available data from the literature on chronic autoimmune gastritis (CAG) in order to increase the awareness of specialists about the modern possibilities for diagnosing the disease, including its early stages. The clinical manifestation of the disease includes possible variants such as gastrointestinal, hematological (first of all, the formation of iron deficiency and B12-deficiency anemia), and neurological variants. Patients with chronic autoimmune gastritis are characterized by comorbidity with other autoimmune diseases. In this paper, data on the most informative serological markers for the diagnosis of CAG, as well as laboratory tests to detect micronutrient deficiencies, information on the characteristic changes in the gastric mucosa, and the prognosis of the disease, are presented. The diagnosis of CAG should be based on a multidisciplinary approach that combines a thorough analysis of a patient's complaints with a mandatory assessment of nutritional status, as well as the results of serological, endoscopic, and histological research methods.

Significance of chromogranin A and synaptophysin in medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) is a rare thyroid carcinoma of C-cell deviation that produces and secretes calcitonin (CT) and chromogranin A (CgA) into the blood. Thus, CT and CgA are immunohistochemical and serum markers for MTCs. MTC occurs in sporadic and inheritable forms. The hallmark of inheritable cases in multiple endocrine neoplasm 2 (MEN2) is MTC. MEN2 cases represent 30% through germline RET proto-oncogene mutation and occur in younger ages involving bilateral thyroid lobes. Sporadic cases are 70% and occur in older ages. CgA and synaptophysin (SPY) are the two most widely used and reliable immunohistochemical markers for neuroendocrine tumors, including MTCs. This study aimed to detect different immunohistochemical staining patterns for CgA and SPY between non-symptomatic small lesions and invading larger aggressive tumors in both MEA2 cases and sporadic cases. There was different CgA and SPY immunostaining in MEA2 cases where small tumors (≤0.3 cm) were lesser immunostained for CgA and SPY, despite intense staining for CT, compared to the larger (≥0.5 cm) tumors, stronger immunostained for CgA. There was also different CgA and SPY immunohistochemical staining in sporadic cases between small lesions (≤0.5 cm) and larger tumors (≥1.0 cm). One small sporadic tumor (0.5 cm × 0.3 cm) was strongly and weakly, patchy stained for CgA and SPY, respectively, while larger sporadic tumors were diffusely and strongly stained for CgA and SPY. Therefore, stronger CgA and SPY immunostaining for larger tumors in both MEA2 and sporadic cases may be used as independent, aggressive immunohistochemical markers for MTCs.

Comparison of the Clinical Features and Outcomes of Gallbladder Neuroendocrine Carcinoma with Those of Adenocarcinoma: A Propensity Score-Matched Analysis

Simple Summary

Neuroendocrine neoplasms (NENs) of the gallbladder (GB) are extremely rare. We aimed to compare the clinical features of GB-NENs with those of adenocarcinomas (ADCs) of the GB. Among 21 patients with GB-NENs, 20 were diagnosed with poorly differentiated small-cell neuroendocrine carcinoma (NEC), and 1 patient had large-cell NEC. At initial presentation, all patients had advanced stages of cancer, with extensive local extension and/or distant metastasis. Nine patients with GB-NEC who underwent surgical resection had a significantly better progression-free survival (PFS) than those who did not undergo surgery. After a propensity score matching with a 1:1 ratio using the American Joint Committee on Cancer (AJCC) stage, age, sex, and operation status, there was no difference in the overall survival or PFS between AJCC stage-matched patients with GB-NEC or GB-ADC. In conclusion, GB-NEC is difficult to diagnose early and has a prognosis similar to that of GB-ADC.

Abstract

Neuroendocrine neoplasms (NENs) of the gallbladder (GB) are extremely rare. We aimed to compare the clinical features, disease progression, management, and prognosis of patients with GB-NENs with those of patients with GB-adenocarcinomas (ADCs). A total of 21 patients with GB-NENs and 206 patients with GB-ADCs, treated at three tertiary medical centers between January 2010 and December 2020, were enrolled. Of the 21 patients with GB-NENs, 20 were diagnosed with poorly differentiated small-cell neuroendocrine carcinomas (NECs), and 1 patient had large-cell NEC. All patients presented with advanced stages of cancer with extensive local extension and/or distant metastasis and non-specific symptoms. Tumor-node-metastasis stage IIIB and IV (A/B) tumors were found in 6 and 15 (1/14) patients, respectively. Nine patients with GB-NEC who underwent surgical resection had a significantly better progression-free survival (PFS) than those who did not undergo surgery. After a propensity score matching with a 1:1 ratio using the American Joint Committee on Cancer stage, age, sex, and operation status, 19 pairs of patients were included. Compared with stage-matched patients with GB-ADC, patients with GB-NEC had similar overall survival and PFS. However, as GB-NEC is rarely diagnosed early, further studies investigating methods for the early diagnosis and improvement in the survival of patients with GB-NEC are needed.

Use of Chromogranin A for Monitoring Patients With Pancreatic Neuroendocrine Neoplasms

OBJECTIVE

We aimed to assess the role of serum chromogranin A (CgA) in monitoring disease status and treatment response in patients with pancreatic neuroendocrine neoplasms (pNENs).

METHODS

We included posttherapy pNENs patients with measured serum CgA levels who underwent 68Ga-labeled tetraazacyclododecanetetraacetic acid-peptide positron emission tomography (PET) imaging between April 2017 and January 2020. Serum CgA levels were determined by enzyme-linked immunosorbent assay. Tumor response was assessed according to the PET response evaluation criteria in solid tumors.

RESULTS

Seventy-seven patients with 101 events were included in this study. Serum CgA levels were significantly higher in patients with active disease and metastasis. The optimal cutoff values for CgA for active and metastatic pNENs diagnosis after treatment were 52.39 (77.8% sensitivity, 80.7% specificity) and 60.18 ng/mL (73.9% sensitivity, 73.1% specificity), respectively. Based on 18 patients with serial CgA measurements and PET imaging, the optimal changes in CgA levels for predicting disease remission and progression were a 28.5% decrease (71.4% sensitivity, 88.2% specificity) and a 21.0% increase (100.0% sensitivity, 75.0% specificity), respectively.

CONCLUSIONS

We concluded that serum CgA levels are associated with disease status and treatment response and may thus provide a helpful biomarker for the monitoring and clinical management of patients with pNENs.

Novel Homozygous Inactivating Mutation in the PCSK1 Gene in an Infant with Congenital Malabsorptive Diarrhea

Proprotein convertase 1/3 (PC1/3), encoded by the PCSK1 gene, is expressed in neuronal and (entero)endocrine cell types, where it cleaves and hence activates a number of protein precursors that play a key role in energy homeostasis. Loss-of-function mutations in PCSK1 cause a recessive complex endocrinopathy characterized by malabsorptive diarrhea and early-onset obesity. Despite the fact that neonatal malabsorptive diarrhea is observed in all patients, it has remained understudied. The aim of this study was to investigate the enteroendocrine pathologies in a male patient with congenital PCSK1 deficiency carrying the novel homozygous c.1034A>C (p.E345A) mutation. This patient developed malabsorptive diarrhea and metabolic acidosis within the first week of life, but rapid weight gain was observed after total parenteral nutrition, and he displayed high proinsulin levels and low adrenocorticotropin. In vitro analysis showed that the p.E345A mutation in PC1/3 resulted in a (near) normal autocatalytic proPC1/3 processing and only partially impaired PC1/3 secretion, but the processing of a substrate in trans was completely blocked. Immunohistochemical staining did not reveal changes in the proGIP/GIP and proglucagon/GLP-1 ratio in colonic tissue. Hence, we report a novel PCSK1 deficient patient who, despite neonatal malabsorptive diarrhea, showed a normal morphology in the small intestine.

Chromogranin A Expression in Rectal Neuroendocrine Tumors Is Associated With More Aggressive Clinical Behavior and a Poorer Prognosis

Although rectal neuroendocrine tumors (NETs) with an L-cell phenotype and small size are generally less clinically serious, the new 2019 World Health Organization (WHO) classification system has categorized all of these lesions as malignant. Identifying biomarkers of rectal NETs is thus important for stratifying their clinical behavior. Chromogranin A protein expression was assessed in 538 endoscopically or surgically resected rectal NETs and compared with clinicopathologic factors to identify its clinical and prognostic significance. All of the rectal NETs analyzed (100%) were synaptophysin positive, but chromogranin A labeling was only detected in 111 cases (20.6%). Chromogranin A expression in the rectal NETs was more commonly associated with older age (50 y and older; P=0.013), male sex (P=0.002), radical resection (P=0.003), large tumor size (≥1 cm; P=0.038), muscularis propria invasion (P=0.002), lymphovascular (P=0.014) and perineural (P<0.001) invasion, an involved resection margin (P=0.028), and lymph node metastasis (P=0.003). Patients with chromogranin A expression had higher plasma chromogranin A levels (P=0.023) than those without chromogranin A expression during follow-up. The 10-year disease-free survival rate in rectal NET patients with chromogranin A expression (91.5%) was significantly shorter than the negative cases (99.7%) by both univariate (hazard ratio=14.438; 95% confidence interval: 2.911-71.598; P<0.001) and multivariate (hazard ratio=12.099; 95% confidence interval, 2.044-71.608; P=0.006) analyses. In summary, rectal NETs that are positive for chromogranin A are less common than those with synaptophysin expression and show more aggressive clinical behavior. Chromogranin A is therefore a prognostic indicator of higher recurrence risk in patients with endoscopically or surgically resected rectal NETs.

Significance of chromogranin A and synaptophysin in pancreatic neuroendocrine tumors

The two most commonly used immunohistochemical markers for neuroendocrine cells and their tumors are chromogranin A (CgA) and synaptophysin (SPY). CgA is a marker for neuroendocrine secretory granules of four pancreatic hormones and gastrin while SPY is a marker for synaptic vesicles in neuroendocrine cells, which release classic neurotransmitters such as acetylcholine and others. CgA is involved in synthesis and secretion of peptide hormones through exocytosis while the function of SPY is elusive. Thirty-five pancreatic neuroendocrine tumors (Pan-NETs) were studied, consisting of 14 insulinomas, 8 gastrinomas, 2 glucagonomas, 6 pancreatic polypeptidomas and 5 non-functioning tumors, and were immunostained for four pancreatic hormones, gastrin, CgA, and SPY. Majority of Pan-NETs were less immunostained for the endocrine hormones and CgA than the normal pancreatic endocrine cells. CgA immunostaining mostly correlates with each hormone staining in non-β-cell tumors, while SPY immunostaining recognizes endocrine cells diffusely in the cytoplasm. CgA immunostaining is less in insulinomas than in non-β-cell tumors, and CgA immunostaining may distinguish CgA-weaker insulinomas from CgA-stronger non-β-cell tumors. CgA immunostaining may be used as an independent marker for biological aggressiveness in non-β-cell Pan-NETs. The serum CgA levels are higher in subjects harboring non-β-cell tumors than those harboring insulinomas, and the serum CgA elevates in parallel to the increasing metastatic tumor mass. Thus, CgA positive immunostaining in Pan-NETs correlates with the elevated serum levels of CgA for diagnosing CgA-positive non-β-cell Pan-NETs and the increasing serum CgA levels indicate increasing metastatic tumor mass.

Pancreatic neuroendocrine tumors: Therapeutic challenges and research limitations

Pancreatic neuroendocrine tumors (PNETs) are known to be the second most common epithelial malignancy of the pancreas. PNETs can be listed among the slowest growing as well as the fastest growing human cancers. The prevalence of PNETs is deceptively low; however, its incidence has significantly increased over the past decades. According to the American Cancer Society’s estimate, about 4032 (> 7% of all pancreatic malignancies) individuals will be diagnosed with PNETs in 2020. PNETs often cause severe morbidity due to excessive secretion of hormones (such as serotonin) and/or overall tumor mass. Patients can live for many years (except for those patients with poorly differentiated G3 neuroendocrine tumors); thus, the prevalence of the tumors that is the number of patients actually dealing with the disease at any given time is fairly high because the survival is much longer than pancreatic ductal adenocarcinoma. Due to significant heterogeneity, the management of PNETs is very complex and remains an unmet clinical challenge. In terms of research studies, modest improvements have been made over the past decades in the identification of potential oncogenic drivers in order to enhance the quality of life and increase survival for this growing population of patients. Unfortunately, the majority of systematic therapies approved for the management of advanced stage PNETs lack objective response or at most result in modest benefits in survival. In this review, we aim to discuss the broad challenges associated with the management and the study of PNETs.

Biomarkers for Pancreatic Neuroendocrine Neoplasms (PanNENs) Management-An Updated Review

Pancreatic neuroendocrine tumors (PanNENs) are rare sporadic cancers or develop as part of hereditary syndromes. PanNENs can be both functioning and non-functioning based on whether they produce bioactive peptides. Some PanNENs are well differentiated while others-poorly. Symptoms, thus, depend on both oncological and hormonal causes. PanNEN diagnosis and treatment benefit from and in some instances are guided by biomarker monitoring. However, plasmatic monoanalytes are only suggestive of PanNEN pathological status and their positivity is typically followed by deepen diagnostic analyses through imaging techniques. There is a strong need for new biomarkers and follow-up modalities aimed to improve the outcome of PanNEN patients. Liquid biopsy follow-up, i.e., sequential analysis on tumor biomarkers in body fluids offers a great potential, that need to be substantiated by additional studies focusing on the specific markers and the timing of the analyses. This review provides the most updated panorama on PanNEN biomarkers.

Secretagogin, a marker for neuroendocrine cells, is more sensitive and specific in large cell neuroendocrine carcinoma compared with the markers CD56, CgA, Syn and Napsin A

A common method to distinguish large cell neuroendocrine carcinoma (LCNEC) from non-neuroendocrine large cell carcinoma (non-NE LCC) is from using specific immunohistochemistry markers, such as CgA, Syn, CD56 and Napsin A, however, the results remain controversial using these markers. Secretagogin (SCGN) is a newly discovered biomarker of neuroendocrine cells. In the present study, the expression of SCGN in 33 cases of human lung large cell carcinoma (LCC), including 17 cases of LCNEC and 16 cases of non-neuroendocrine (NE) LCC and lung cancer cell lines (A549, H1650, H358, H292 and H661). The association between SCGN expression and the clinicopathological characteristics of patients, including sex, age, clinical stage and metastasis, was analyzed. The results revealed that the different lung cancer cell lines had different expression levels of SCGN, and the SCGN protein was localized in the nucleus and cytoplasm of A549 cells detected using immunofluorescence. A total of 54.5% (18/33) of specimens positively expressed the SCGN protein. Of the 17 patients with LCNEC, only 23.5% (4/17) of cases were CgA positive, 35.29% (6/17) were Syn positive, 41.2% (7/17) were CD56 positive, and 41.2% (7/17) were Napsin A positive. However, SCGN was positively detected in 94.1% (16/17) of patients with LCNEC, which was more frequent compared with that in CgA, Syn, CD56 and Napsin A. Analysis of the clinical characteristics indicated that SCGN expression was only significantly associated with pathological type in patients with lung cancer (P<0.001). Furthermore, a positive correlation was observed between SCGN expression and CgA, Syn, and CD56 expression in patients with LCNEC. SCGN was co-localized with the NE markers (CgA, Syn, and CD56) in A549 lung cancer cells and in LCNEC tissues. Thus, SCGN displayed more sensitivity and specificity in lung cancer cells with NE differentiation. A combined analysis of SCGN and other common NE markers may be a potential tool for diagnosing these tumors.

P53, Somatostatin receptor 2a and Chromogranin A immunostaining as prognostic markers in high grade gastroenteropancreatic neuroendocrine neoplasms

Background

High grade gastroenteropancreatic (GEP) neuroendocrine neoplasms (NEN) with a Ki67 proliferation index > 20%, include well-differentiated tumours grade 3 (NET G3) and poorly differentiated (PD) neuroendocrine carcinomas (NEC). Abnormal p53-expression is a feature of PD tumours, while expression of chromogranin A (CgA) and somatostatin-receptor 2a (SSTR-2a) may be a feature of well-differentiated tumours. The aim of this study was to elucidate the expression and prognostic value of these three markers in 163 GEP-NEN patients with a Ki67-index > 20%.

Method

Clinical data, histopathology and overall survival were analysed according to Kaplan-Meier’s method and Cox regression. The expression of SSTR-2a, CgA and synaptophysin was analysed in tumour specimens by immunohistochemistry, and semi-quantitatively scored as negative (< 5%), heterogeneously positive (5–30%) or strongly positive (> 30%). P53 was defined as normal when scored as heterogeneously positive (1–30%), and abnormal when negative (0%) or strongly positive (> 30%).

Results

In multivariate analysis, better survival was observed among patients with heterogeneously positive p53 compared to strongly positive (p < 0.001). When dichotomised, tumours with a heterogeneously positive p53 vs. negative and strongly positive p53 also showed a significantly better survival (p = 0.002).

Survival was significantly worse for negative CgA compared to heterogeneously positive CgA (p = 0.02). Strongly positive SSTR-2a expression was found in 26% of the 163 included patients. Well-differentiated morphology correlated with strong expression of SSTR-2a and CgA, and heterogeneously positive p53-staining, and was more frequent in pancreatic primaries. In pancreatic primaries, strongly positive SSTR-2a was associated with longer survival (univariate analysis, p = 0.02). A significantly lower Ki67 proliferation index was found in patients with a heterogeneously positive p53, a positive SSTR-2a and CgA expression.

Conclusion

Our results suggest that abnormal p53-expression is an independent negative prognostic marker in GEP-NEN with a Ki67-index > 20%. Patients with heterogeneously positive p53 had the best prognosis. SSTR-2a was a positive prognostic marker in pancreatic NEN. Negative CgA was associated with a significantly worse OS compared to heterogeneously positive CgA-expression in a multivariate sub-analysis. Lower Ki67 index correlated significantly with heterogeneously positive p53, positive SSTR-2a and CgA expression.

Prognostic and predictive factors on overall survival and surgical outcomes in pancreatic neuroendocrine tumors: recent advances and controversies

Introduction: Recent advances in diagnostic modalities and therapeutic agents have raised the importance of prognostic factors in predicting overall survival, as well as predictive factors for surgical outcomes, in tailoring therapeutic strategies of patients with pancreatic neuroendocrine neoplasms (panNENs).Areas covered: Numerous recent studies of panNEN patients report the prognostic values of a number of clinically related factors (clinical, laboratory, imaging, treatment-related factors), pathological factors (histological, classification, grading) and molecular factors on long-term survival. In addition, an increasing number of studies showed the usefulness of various factors, specifically biomarkers and molecular makers, in predicting recurrence and mortality related to surgical treatment. Recent findings (from the last 3 years) in each of these areas, as well as recent controversies, are reviewed.Expert commentary: The clinical importance of prognostic and predictive factors for panNENs is markedly increased for both overall outcome and post resection, as a result of recent advances in all aspects of the diagnosis, management and treatment of panNENs. Despite the proven prognostic utility of routinely used tumor grading/classification and staging systems, further studies are required to establish these novel prognostic factors to support their routine clinical use.

Specific and Non-Specific Biomarkers in Neuroendocrine Gastroenteropancreatic Tumors

The diagnosis of neuroendocrine tumors (NETs) is a challenging task: Symptoms are rarely specific, and clinical manifestations are often evident only when metastases are already present. However, several bioactive substances secreted by NETs can be included for diagnostic, prognostic, and predictive purposes. Expression of these substances differs between different NETs according to the tumor hormone production. Gastroenteropancreatic (GEP) NETs originate from the diffuse neuroendocrine system of the gastrointestinal tract and pancreatic islets cells: These tumors may produce many non-specific and specific substances, such as chromogranin A, insulin, gastrin, glucagon, and serotonin, which shape the clinical manifestations of the NETs. To provide an up-to-date reference concerning the different biomarkers, as well as their main limitations, we reviewed and summarized existing literature.

Tumor markers: myths and facts unfolded

OBJECTIVE

The purpose of this article is to review the most commonly used tumor markers in abdominal and pelvic tumors, describe their limitations and explain how to use them in the context of known cancer in order to optimize multidisciplinary care of oncologic patients.

CONCLUSION

Tumor markers are important for the diagnosis, staging, monitoring of treatment and detection of recurrence in many cancers. This knowledge is crucial in the daily interpretation of images of oncologic and non-oncologic patients. However, radiologists should also be aware of the limitations of the most commonly used tumor markers and they should not be used solely, but interpreted in conjunction with diagnostic imaging, clinical history and physical examination that will help optimize the multidisciplinary care and management of oncologic patients.

Neuroendocrine neoplasms: current and potential diagnostic, predictive and prognostic markers

Some biomarkers for functioning and non-functioning neuroendocrine neoplasms (NENs) are currently available. Despite their application in clinical practice, results should be interpreted cautiously. Considering the variable sensitivity and specificity of these parameters, there is an unmet need for novel biomarkers to improve diagnosis and predict patient outcome. Nowadays, several new biomarkers are being evaluated and may become future tools for the management of NENs. These biomarkers include (1) peptides and growth factors; (2) DNA and RNA markers based on genomics analysis, for example, the so-called NET test, which has been developed for analyzing gene transcripts in circulating blood; (3) circulating tumor/endothelial/progenitor cells or cell-free tumor DNA, which represent minimally invasive methods that would provide additional information for monitoring treatment response and (4) improved imaging techniques with novel radiolabeled somatostatin analogs or peptides. Below we summarize some future directions in the development of novel diagnostic and predictive/prognostic biomarkers in NENs. This review is focused on circulating and selected tissue markers.

Serum chromogranin A for the diagnosis of gastroenteropancreatic neuroendocrine neoplasms and its association with tumour expression

The aim of the present study was to assess the clinical value of serum chromogranin A (CgA) levels in patients with gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) and to compare them with tumour expression of CgA. A total of 109 consecutive patients with confirmed GEP-NENs were enrolled in this prospective study between December 2012 and August 2016, including 73 patients with primary or recurrent GEP-NENs and 36 patients with GEP-NENs that were treated following surgery. Furthermore, 30 patients with benign gastrointestinal diseases and 30 healthy volunteers served as control groups. Serum CgA levels were measured by ELISA, using different reference values, in order to evaluate its diagnostic efficacy. Serum neuron-specific enolase was also measured to evaluate its diagnostic efficacy and analyse its association with serum CgA levels. The levels of CgA, synaptophysin and neural cell adhesion molecule 1 in the tumour tissue were assessed by immunohistochemical assays. The results indicated that serum CgA levels were significantly higher in patients with GEP-NENs compared with the control groups (P<0.05). No association was observed between serum CgA levels and tumour grade (G1, G2 and G3), but serum CgA levels differed significantly between patients with GEP-NENs of different origins (P<0.05). A serum CgA cut-off value of 85.3 ng/ml was associated with high sensitivity (64.4%) and specificity (92.7%). Different reference values were recommended for NENs of different origins, with serum CgA cut-off values of 96.72, 51.13 and 86.19 ng/ml for the stomach, intestines and pancreas, respectively. The serum CgA levels were consistent with the CgA expression in the tumour. In conclusion, serum CgA may serve as a circulating pathological biomarker for the diagnosis of GEP-NENs. The use of different reference values for different tumour origins may improve the diagnostic efficacy of CgA for GEP-NENs. A cut-off value of 85.3 ng/ml is recommended in the Chinese population.

Prognostic significance of Chromogranin A in small pancreatic neuroendocrine tumors

BACKGROUND

The incidence of nonfunctional pancreatic neuroendocrine tumors ≤2cm is rising. The biologic behavior of these tumors is variable; thus, their management remains controversial. Chromogranin A upregulation is a useful diagnostic biomarker of neuroendocrine tumors; however, the prognostic significance of Chromogranin A is unclear. The objective of this study was to determine whether Chromogranin A levels have prognostic value in pancreatic neuroendocrine tumor patients and may help guide management.

METHODS

We evaluated the National Cancer Database over a 10-year period (2004-2013). Patients with pancreatic neuroendocrine tumors measuring ≤2cm, without distant metastases, were identified and categorized as Chromogranin A high (>420ng/mL) or Chromogranin A low (≤420ng/mL), and those lacking data on Chromogranin A levels were excluded from the study. Univariate and multivariate analyses were performed using Cox proportional hazards model. Cut-point determination was performed using the Contal and O'Quigley method.

RESULTS

Of the 445 eligible patients, 352 (79%) were Chromogranin A low and 93 (21%) were Chromogranin A high. Median Chromogranin A level was 71ng/mL (interquartile range, 24-294ng/mL). Chromogranin levels were associated with clinical nodal status and grade. Furthermore, on multivariate analysis, Chromogranin A levels (Chromogranin A high versus Chromogranin A low) independently predicted overall survival after controlling for tumor size, grade, clinical nodal status, and academic status of the facility (hazard ratio: 7.90, 95%CI: 2.34-26.69, P = .001). The greatest benefit of surgical resection was noted in patients in the Chromogranin A high subgroup (log-rank P <.001).

CONCLUSION

Serum Chromogranin A levels can be incorporated in surgical decision-making for patients with small pancreatic neuroendocrine tumors. Patients in the Chromogranin A low group can be considered for observation, whereas patients in the Chromogranin A high group should be strongly considered for resection.

Chromogranin A in the Follow-up of Gastroenteropancreatic Neuroendocrine Neoplasms: Is It Really Game Over? A Systematic Review and Meta-analysis

OBJECTIVES

Little is known about chromogranin A (CgA) during follow-up of gastroenteropancreatic neuroendocrine neoplasms. We hypothesized that serial CgA monitoring might be useful for the assessment of tumor progression, and we performed a systematic review of the literature and meta-analysis.

METHODS

A bibliographical search was performed in PubMed using "chromogranin A" and "neuroendocrine tumors" and "follow-up" and "biomarker" to identify all pertinent articles published in the last 10 years.

RESULTS

Eight studies were included in current meta-analysis. Chromogranin A as a follow-up marker shows sensitivity between 46% and 100% and specificity between 68% and 90%. The meta-analysis results showed an overall accuracy of 84% (95% confidence interval [CI], 81-86.6), a cumulative sensitivity of 74.6% (95% CI, 61.9-85.4), and a cumulative specificity of 84.7% (95% CI, 81.3-87.7). These data indicate that circulating CgA has a better overall accuracy in the follow-up setting; it can be used to rule the diagnosis of recurrence/progression in, rather than to rule it out.

CONCLUSIONS

Chromogranin A is more reliable when used to monitor disease progression and response to treatment and for the early detection of recurrence after treatment rather than in the diagnostic setting. It is more sensible to use this marker in those cases where the initial values were impaired.

Effect of Lanreotide Depot/Autogel on Urinary 5-Hydroxyindoleacetic Acid and Plasma Chromogranin A Biomarkers in Nonfunctional Metastatic Enteropancreatic Neuroendocrine Tumors

BACKGROUND

Urinary 5-hydroxyindoleacetic acid (5-HIAA) is an established biomarker in neuroendocrine tumors and carcinoid syndrome; however, its role in nonfunctional neuroendocrine tumors is not defined. We present post hoc data on urinary 5-HIAA and plasma chromogranin A (CgA) from the CLARINET study.

METHODS

Patients with well- or moderately differentiated, nonfunctioning, locally advanced or metastatic enteropancreatic neuroendocrine tumors were randomized to deep subcutaneous lanreotide depot/autogel 120 mg or placebo once every 28 days for 96 weeks. Tumor response, evaluated centrally (RECIST 1.0), and progression-free survival (PFS) were assessed by treatment and biochemical response, defined as (a) baseline >upper limit of normal (ULN, 41.6 μmol per day 5-HIAA; 98.1 μg/L CgA) and (b) ≥50% decrease from baseline and to ≤ULN value on study.

RESULTS

Forty-eight percent (82 of 171; lanreotide, n = 45; placebo, n = 37) and 66% (129 of 195; lanreotide, n = 65; placebo, n = 64) of randomized patients had 5-HIAA and CgA > ULN at baseline. Among patients with >ULN baseline values who did not progress after 96 weeks of treatment, significantly greater reductions in 5-HIAA and CgA were observed in lanreotide-treated versus placebo-treated patients throughout the study (all p < .05). PFS was significantly prolonged among 5-HIAA responders versus nonresponders (median not reached vs. 16.2 months, p < .0001; hazard ratio [HR] = 0.21, 95% confidence interval [CI], 0.09-0.48) and CgA responders versus nonresponders (median not reached vs. 16.2 months, p = .0070; HR = 0.30, 95% CI, 0.12-0.76), regardless of treatment arm. PFS was also significantly prolonged among lanreotide-treated 5-HIAA responders versus nonresponders (p = .0071) but was not significantly different among placebo-treated 5-HIAA responders versus nonresponders. There were no significant differences in PFS between lanreotide-treated CgA responders versus nonresponders or between placebo-treated CgA responders versus nonresponders.

CONCLUSIONS

The 5-HIAA findings are noteworthy because they occurred in patients with nonfunctioning enteropancreatic neuroendocrine tumors. Monitoring 5-HIAA and CgA may be useful when treating patients with nonfunctional neuroendocrine tumors.

IMPLICATIONS FOR PRACTICE

Current guidelines focus only on the monitoring of 5-hydroxyindoleacetic acid (5-HIAA) in the diagnosis and management of functional neuroendocrine tumors with carcinoid syndrome. The current post hoc analysis of patients with nonfunctional enteropancreatic neuroendocrine tumors in the CLARINET study demonstrated that measuring and following both 5-HIAA and chromogranin A as biomarkers of disease progression may be useful in the management of patients with nonfunctional neuroendocrine tumors.

Prognostic value of chromogranin A in patients with GET/NEN in the pancreas and the small intestine

The aim of this study was to evaluate the clinical usefulness of the chromogranin A (CgA) determination in patients with neuroendocrine neoplasms (NENs) of the digestive system and to analyse the association between concentration of the marker and progression-free survival (PFS) and overall survival (OS). Serum concentrations of CgA were determined before the treatment in 131 patients with NENs, including patients with tumours located in the pancreas, the small intestine, caecum, appendix and in the colon. No significant associations were identified in CgA concentrations between the control group and patients with NENs in appendix and colon. In patients with NENs of the pancreas and NENs of the small intestine and caecum, increased CgA levels were associated with lymph node involvement, distant metastases and a baseline liver involvement. Analyses revealed significantly higher CgA concentrations in patients with active disease compared to those without symptoms of NEN. In patients with NENs of the pancreas, CgA concentration was correlated with tumour grade and Ki67. Significantly higher CgA levels were also found in patients who died compared to those who lived. Analyses of PFS and OS revealed that CgA concentration was not a prognostic factor in patients with NENs of the pancreas. In patients with NENs of the small intestine and caecum, increased CgA concentrations are independent, poor prognostic factors for both PFS and OS. In conclusion, in patients with NENs in pancreas, CgA levels are associated with disease progression, while in patients with NENs in small intestine and caecum, its concentration is a predictive indicator for PFS and OS.

A score derived from routine biochemical parameters increases the diagnostic accuracy of chromogranin A in detecting patients with neuroendocrine neoplasms

BACKGROUND

Chromogranin A (CgA) is a valuable biomarker for detection and follow-up of patients with neuroendocrine neoplasms (NENs). However, various comorbidities may influence serum CgA, which decreases its diagnostic accuracy. We aimed to investigate which laboratory parameters are independently associated with increased CgA in real-life setting and to develop a scoring system, which could improve the diagnostic accuracy of CgA in detecting patients with NENs.

METHODS

This retrospective study included 55 treatment naïve patients with NENs and160 patients with various comorbidities but without NEN (nonNENs). Scoring system (CgA-score) was developed based on z-scores obtained from receiver operating curve analysis for each parameter that was associated with elevated serum CgA in nonNENs.

RESULTS

CgA correlated positively with serum BUN, creatinine, α2-globulin, red-cell distribution width, erythrocyte sedimentation rate, plasma glucose and correlated inversely with hemoglobin, thrombocytes and serum albumin. Serum CgA was also associated with the presence of chronic renal failure, arterial hypertension and diabetes and the use of PPI. In the entire study population, CgA showed an area under the curve of 0.656. Aforementioned parameters were used to develop a CgA-score. In a cohort of patients with CgA-score <12.0 (N = 87), serum CgA >156.5 ng/ml had 77.8% sensitivity and 91.5% specificity for detecting NENs (AUC 0.841, 95% CI 0.713-0.969, P < 0.001). Serum CgA had no diagnostic value in detecting NENs in patients with CgA-score >12.0 (AUC 0.554, 95% CI 0.405-0.702, P = 0.430).

CONCLUSIONS

CgA-score encompasses a wide range of comorbidities and represents a promising tool that could improve diagnostic performance of CgA in everyday clinical practice.

Effective preparation of a monoclonal antibody against human chromogranin A for immunohistochemical diagnosis

BACKGROUND

Human chromogranin A (CgA) is a ~ 49 kDa secreted protein mainly from neuroendocrine cells and endocrine cells. The CgA values in the diagnosis of tumor, and in the potential role in prognostic and predictive tumor as a biomarker.

RESULTS

The synthesized gene of CgA coding area was cloned and expressed as fusion protein CgA-His in procaryotic system. Then the purified CgA-His protein was mixed with QuickAntibody-Mouse5W adjuvant, and injected into mice. The CgA-His protein was also used as coating antigen to determine the antiserum titer. By screening, a stable cell line named 4E5, which can generate anti-CgA monoclonal antibody (mAb), was obtained. The isotype of 4E5 mAb was IgG_2b, and the chromosome number was 102 ± 4. Anti-CgA mAb was purified from ascites fluid, and the affinity constant reached 9.23 × 10⁹ L/mol. Furthermore, the specificity of the mAb was determined with ELISA, western blot and immunohistochemistry. Results indicated that the mAb 4E5 was able to detect chromogranin A specifically and sensitively.

CONCLUSIONS

A sensitive and reliable method was successfully developed for rapid production of anti-CgA mAb for immunohistochemistry diagnosis in this study, and the current study also provides conclusive guidelines for preparation of mAbs and implements in immunohistochemistry diagnosis.

Utility of chromogranin B compared with chromogranin A as a biomarker in Japanese patients with pancreatic neuroendocrine tumors

Objective

Currently, serum chromogranin A is a well-established biomarker for pancreatic neuroendocrine tumors; however, other pancreatic diseases, oral use of a proton pump inhibitor and renal impairment can affect chromogranin A. Meanwhile, chromogranin B, belonging to the same granin family as chromogranin A, is not fully examined in these conditions. The present study aimed to evaluate the utility of chromogranin B as a pancreatic neuroendocrine tumor biomarker.

Methods

Serum chromogranin B levels were determined by radioimmunoassay and serum chromogranin A levels by enzyme-linked immunosorbent assay in pancreatic neuroendocrine tumor (n = 91) and other pancreatic conditions, and in healthy people (n = 104), to assess the relationships with clinical features.

Results

The diagnostic ability of chromogranin B was as good as chromogranin A. The area under the curve was 0.79 for chromogranin B (sensitivity/specificity: 72%/77%), and 0.78 for chromogranin A (sensitivity/specificity: 79%/64%). Chromogranin B was not affected by proton pump inhibitor use and age, which affected chromogranin A. The number of cases without liver metastases was larger in pancreatic neuroendocrine tumor patients with positive chromogranin B and negative chromogranin A. Though chromogranin A significantly elevated cases with proton pump inhibitor treatment and had positive correlation with age, chromogranin B did not have the tendencies. However, both chromogranin B and chromogranin A elevated in the case with renal impairment. In addition, the logistic regression analysis showed that chromogranin B was superior to chromogranin A in differentiation of pancreatic neuroendocrine tumor from other pancreatic diseases.

Conclusions

Compared with chromogranin A, chromogranin B may be more useful during proton pump inhibitor treatment and can detect tumors without liver metastases. In addition, chromogranin B may be an excellent biomarker when differentiation of pancreatic neuroendocrine tumor from other pancreatic diseases is required.

Sex comb on midleg like-2 is a novel specific marker for the diagnosis of gastroenteropancreatic neuroendocrine tumors

Sex comb on midleg like-2 (SCML2) is a polycomb-group protein that encodes transcriptional repressors essential for appropriate development in the fly and in mammals. On the basis of previous findings, the present study aimed to explore the possibility of developing SCML2 into a new diagnostic marker for gastroenteropancreatic neuroendocrine tumors (GEP-NETs). A total of 64 paired GEP-NET tissues and adjacent non-tumorous tissues were obtained from patients who had undergone surgical resection between January 2009 and January 2014, and the expression of SCML2 and two neuroendocrine markers, namely synaptophysin (Syn) and chromogranin A (CgA), in the tissues was assessed by immunohistochemistry. Strong SCML2 staining was observed predominantly in the cell nuclei of GEP-NET tissues, and the overall expression rate and staining intensity of SCML2 were higher than those of Syn or CgA, respectively. Spearman rank correlation analysis demonstrated that SCML2 was not correlated with either Syn or CgA, while the combined detection of SCML2 with Syn or with CgA increased the diagnostic sensitivity to 100%. SCML2 expression in GEP-NETs was associated with several clinicopathological parameters, such as histological type, tumor grade, depth of invasion and clinical stage. Kaplan-Meier survival curves revealed that patients with higher SCML2 expression had lower survival rates than those with lower expression levels, while Cox proportional hazards regression analysis revealed that SCML2 was not an independent prognostic factor for GEP-NET patients. Therefore, SCML2 may have potential as a specific marker for joint use with other markers to improve the diagnostic efficiency of GEP-NETs.

The role of elevated serum procalcitonin in neuroendocrine neoplasms of digestive system

INTRODUCTION

Elevated serum procalcitonin (PCT) was reported in patients with certain type of neuroendocrine neoplasms (NENs).

OBJECTIVE

The aim of this study was to assess the role of elevated serum PCT in NENs from digestive system.

PATIENTS AND METHODS

Serum PCT and serum CgA level were measured in 155 patients with NENs from digestive system.

RESULTS

Elevated serum PCT was found in 63 patients (40.6%). Grade 3 disease was a significant factor associated with elevated serum PCT (OR, 9.24; 95%CI, 3.04-28.08; P<0.001). Serum PCT level was significantly decreased after treatment both in patients with stable disease (P=0.003) and patients with partial remission (P=0.001). In these patients, serum PCT level significantly increased again at the time of progression disease (P=0.001). Elevated serum PCT was a significant factor of worse survival (HR, 2.86; 95%CI, 1.36-6.03; P=0.006). Compared with patients with normal serum PCT and CgA level, patients with either PCT or CgA elevated and patients with both PCT and CgA elevated had progressively worse survival. Additionally, PCT expression in tumor cells was found in 24.0% of patients but did not correlate with other clinicopathological factors, including serum PCT.

CONCLUSIONS

Serum PCT is elevated in part of patients with NENs of digestive system, especially in patients with grade 3 disease. Serum PCT level can help evaluate treatment response and its elevation indicates poor prognosis. Combination of serum PCT and CgA can improve outcome prediction.

Clinicopathological Features and Prognostic Factors of Colorectal Neuroendocrine Neoplasms

Background. Limited research is available regarding colorectal NENs and the prognostic factors remain controversial. Materials and Methods. A total of 68 patients with colorectal NENs were studied retrospectively. Clinical characteristics and prognosis between colonic and rectal NENs were compared. The Cox regression models were used to evaluate the predictive capacity. Results. Of the 68 colorectal NENs patients, 43 (63.2%) had rectal NENs, and 25 (36.8%) had colonic NENs. Compared with rectal NENs, colonic NENs more frequently exhibited larger tumor size (P < 0.0001) and distant metastasis (P < 0.0001). Colonic NENs had a worse prognosis (P = 0.027), with 5-year overall survival rates of 66.7% versus 88.1%. NET, NEC, and MANEC were noted in 61.8%, 23.5%, and 14.7% of patients, respectively. Multivariate analyses revealed that tumor location was not an independent prognostic factor (P = 0.081), but tumor size (P = 0.037) and pathological classification (P = 0.012) were independent prognostic factors. Conclusion. Significant differences exist between colonic and rectal NENs. Multivariate analysis indicated that tumor size and pathological classification were associated with prognosis. Tumor location was not an independent factor. The worse outcome of colonic NENs observed in clinical practice might be due not only to the biological differences, but also to larger tumor size in colonic NENs caused by the delayed diagnosis.

Systemic therapies for advanced gastroenteropancreatic neuroendocrine tumors

Neuroendocrine tumors are a heterogeneous group of malignancies, characterised by production of hormones and vasoactive peptides. The incidence of gastroenteropancreatic neuroendocrine tumors (GEP-NET) is rising, and they have the highest prevalence amongst upper gastro-intestinal tumors. Diagnosis remains challenging due to wide variations in presentation and slow onset of symptoms. A multi-disciplinary approach is vital in appropriately managing the diverse spectrum of GEP-NET. Areas covered: Investigations in GEP-NET and biomarkers are described. Moreover, all available therapeutic options for GEP-NET including surgery, somatostatin analogues, targeted agents, Peptide Receptor Radionuclide Therapy and chemotherapy are also discussed. Expert commentary: The landscape of management has changed significantly in the last decade as a result of many practice-changing clinical trials. Long- acting somatostatin analogues are used not only for symptom control but also for their anti-proliferative effect. Targeted agents, such as everolimus and sunitinib, have improved PFS in GEP-NET. The recently presented NETTER-1 trial confirms the place of peptide receptor radionuclide treatment (PRRT) in treating NET. While chemotherapy remained an important option for high grade tumors. Despite promising results from recent trials, challenges include establishing the optimal sequencing of therapies to optimize outcome and preserve the quality of life.

Current progress in diagnosis and therapy of neuroendocrine neoplasms of the digestive system

Neuroendocrine neoplasms (NENs) are a group of heterogeneous, biologically diverse, rare malignancies originated from the peptidergic neurons and neuroendocrine cells. In recent years, the incidence of NENs has been increasing gradually. They typically arise in the pancreas and gastrointestinal tract. Chromogranin A (CgA) has long been used as an important broad-spectrum marker for the identification of NENs. The diagnosis is based on histopathology demonstrating neuroendocrine features such as positive staining for chromogranin A and specific hormones such as gastrin, proinsulin, vasoactive intestinal peptide (VIP) and glucagon. In addition, radiological modalities including computed tomography (CT), positron emission tomography and computed tomography (PET/CT), magnetic resonance imaging (MRI), ultrasound (US), endoscopic ultrasound (EUS), and somatostatin receptor scintigraphy (SRS) can help establish a diagnosis. Surgery is still one of the cornerstones in the management of NENs. This article reviews the current progress in the diagnosis and therapy of NENs of the digestive system, including the pathological features and clinical diagnostic modalities for primary esophageal, gastric, duodenal, small intestinal, appendiceal, colonic, rectal, hepatic, gallbladder, extrahepatic bile duct, and pancreatic NENs, according to a revised system of classification, nomenclature and grading of NENs proposed by the fourth edition of "World Health Organization (WHO) classification of tumours of the digestive system" in 2010, and consensus of diagnosis and treatment of gastroenteropancreatic NENs (GEP-NENs) proposed by the Chinese Society of Clinical Oncology (CSCO) in 2013.

Circulating Chromogranin A as A Marker for Monitoring Clinical Response in Advanced Gastroenteropancreatic Neuroendocrine Tumors

Chromogranin A (CgA), present in the chromaffin granules of neuroendocrine cells, is a useful biomarker for the diagnosis of patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs). This study was conducted to investigate the potential role of circulating CgA in monitoring clinical response in Chinese patients with advanced GEP-NETs. Eighty patients with advanced GEP-NETs treated in Peking University Cancer Hospital from September 2011 to May 2014 and 65 healthy individuals were included in this study. Serum CgA levels were analyzed for relationship with patient's baseline characteristics and clinical outcome. Median CgA levels were significantly higher in patients with advanced GEP-NETs than in healthy individuals (93.8 ng/mL vs. 37.1 ng/mL; P<0.01), as well as significantly higher in patients with carcinoid syndrome or liver metastasis than in those without carcinoid syndrome (298.8 ng/mL vs. 82.9 ng/mL; P = 0.011) or liver metastasis (137.0 ng/mL vs. 64.4 ng/mL; P = 0.023). A CgA cutoff value of 46.2 ng/mL was used in this study with a sensitivity of 78.8% and specificity of 73.8%. Patients with CgA levels higher than 46.2 ng/mL had a worse prognosis than patients with CgA levels lower than 46.2 ng/mL (P = 0.045). Notably, a weak correlation was observed between changes in serum CgA levels and clinical response to the IP regimen as well as SSAs. Our data also indicate that serum CgA could be a useful indicator of patient prognosis though there is more research required in order to validate such claims.

CEA Level, Radical Surgery, CD56 and CgA Expression Are Prognostic Factors for Patients With Locoregional Gastrin-Independent GNET

Gastrin-independent gastric neuroendocrine tumors (GNETs) are highly malignant. Radical resections and lymphadenectomy are considered to be the only possible curative treatment for these tumors. However, the prognosis of gastrin-independent GNETs is not well defined. In this study, we identified prognostic factors of locoregional gastrin-independent GNETs.All patients diagnosed with locoregional gastrin-independent GNETs between 2000 and 2014 were included in this retrospective study. Clinical characteristics, blood tests, pathological characteristics, treatments, and follow-up data of the patients were collected and analyzed.Of the 66 patients diagnosed with locoregional gastrin-independent GNETs, 57 (86.4%) received radical resections, 7 (10.6%) with palliative resection, 1 (1.5%) with gastrojejunostomy, and 1 (1.5%) with exploration surgeries. The median survival time for these patients was 19.0 months (interquartile range, 11.0-38.0). The 1-, 3-, and 5-year survival rates were 72%, 34%, and 28%, respectively. Multivariate analysis indicated that carcinoembryonic antigen (CEA) level (P = 0.04), radical resection (P = 0.04), and positive Cluster of Differentiation 56 (CD56) expression (P = 0.016) were significant prognostic factors on overall survival rate. Further univariate and multivariate analysis of 57 patients who received radical resections found that CgA expression (P = 0.35) and CEA level (P = 0.33) are independent prognostic factors.Gastrin-independent GNETs had poor prognosis. Serum CEA level, radical surgery, CD56 and CgA expression are markers to evaluate the survival of patients with locoregional gastrin-independent GNETs.

Differences and Similarities in the Clinicopathological Features of Pancreatic Neuroendocrine Tumors in China and the United States: A Multicenter Study

The presentation, pathology, and prognosis of pancreatic neuroendocrine tumors (PNETs) in Asian patients have not been studied in large cohorts. We hypothesized that the clinicopathological features of PNETs of Chinese patients might be different from those of US patients. The objectives of this study were to address whether PNETs in Chinese patients exhibit unique clinicopathological features and natural history, and can be graded and staged using the WHO/ENETS criteria. This is a retrospective review of medical records of patients with PNETs in multiple academic medical centers in China (7) and the United States (2). Tumor grading and staging were based on WHO/ENETS criteria. The clinicopathological features of PNETs of Chinese and US patients were compared. Univariate and multivariate analyses were performed to find associations between survival and patient demographics, tumor grade and stage, and other clinicopathological characteristics. A total of 977 (527 Chinese and 450 US) patients with PNETs were studied. In general, Chinese patients were younger than US patients (median age 46 vs 56 years). In Chinese patients, insulinomas were the most common (52.2%), followed by nonfunctional tumors (39.7%), whereas the order was reversed in US patients. Tumor grade distribution was similar in the 2 countries (G1: 57.5% vs 55.0%; G2: 38.5% vs 41.3%; and G3: 4.0% vs 3.7%). However, age, primary tumor size, primary tumor location, grade, and stage of subtypes of PNETs were significantly different between the 2 countries. The Chinese nonfunctional tumors were significantly larger than US ones (median size 4 vs 3 cm) and more frequently located in the head/neck region (54.9% vs 34.8%). The Chinese and US insulinomas were similar in size (median 1.5 cm) but the Chinese insulinomas relatively more frequently located in the head/neck region (48.3% vs 26.1%). Higher grade, advanced stage, metastasis, and larger primary tumor size were significantly associated with unfavorable survival in both countries. Several clinicopathological differences are found between Chinese and US PNETs but the PNETs of both countries follow a similar natural history. The WHO tumor grading and ENETS staging criteria are applicable to both Chinese and US patients.

Radiochemotherapy Versus Surgery in Nonmetastatic Anorectal Neuroendocrine Carcinoma: A Multicenter Study by the Association des Gastro-Entérologues Oncologues

Neuroendocrine carcinomas (NEC) of the anus or the rectum are a rare disease, accounting for less than 1% of all digestive malignancies. Most are metastatic at diagnosis and treated with a platinum-based chemotherapy. No guidelines for localized tumors exist. The purpose of this study was to describe the characteristics of anorectal localized NEC, their management and their outcomes.We retrospectively reviewed patients from 11 French centers with anorectal localized NEC. We compared 2 therapeutic managements: surgery (group A) versus chemotherapy with or without radiation (group B). Progression-free survival (PFS) and overall survival (OS) were estimated with the Kaplan-Meier method.A total of 24 patients were identified with a median follow-up of 25 months (3-60 months). Median age was 63 years old and 17 had a rectal tumor (71%). Mean Ki-67 was 72% (range: 20-100), and 75% of the tumors had a high proliferative index (Ki-67 > 50%). Global PFS and OS were 13.1 and 44.1 months, respectively. Thirty-seven percent of patients were in group A and 63% in group B. There was no difference between group A and group B, whether in terms of PFS (13.0 months vs. 13.2 months, P = 0.75) or OS (49.1 months vs. 39.2 months, P = 0.42).In patients with anorectal localized NEC, chemotherapy with or without radiation obtained a similar outcome as surgery and this conservative approach could be deemed a reasonable option.