Neuroendocrine Tumor Markers Research Articles

Liver metastasized pancreatic neuroendocrine tumor in a 17-year-old female: A case report.

Pancreatic neuroendocrine tumors (PNETs) are rare and often misdiagnosed due to their vague symptoms and tumor heterogeneity. Early detection using computed tomography (CT) is essential, particularly in regions without access to advanced diagnostic tools like immunohistochemistry and genetic testing. Neuroendocrine tumors (NETs) are rare tumors in adults and extremely rare in the pediatric population, as pancreatic NETs (pNETs) have an incidence rate of <0.1 per million. We present a case of a 17-year-old female with a liver metastasized pNET. A 17-year-old female with a history of intermittent abdomen-back pain presented to the clinic with severe upper abdominal pain radiating to the shoulder. The routine tests were normal. An ultrasound showed multiple lesions in the liver, which were confirmed by a computed tomography (CT) that uncovered a pancreatic lesion too. A liver biopsy proved it was a metastasized pNET with positive NET markers on IMC staining. The metaiodobenzylguanidine (MIBG) scan flared the liver lesion. The patient was started on Octreotide long-acting release (LAR) 30 mg once monthly. The rarity of these tumors makes their diagnosis difficult, but they should not be omitted and must be considered when there are long-lasting symptoms that are not compatible with common illnesses. These tumors are curable in their early stages.

Prognostic and predictive significance of p53 and ATRX in neuroendocrine neoplasms of GIT and pancreas and their utility as an adjunct to accurate diagnosis-An eight-year retrospective study.

Neuroendocrine neoplasms of gastrointestinal tract (GIT)and pancreas are heterogenous tumors. World Health Organization (WHO)2019 classification introduced Grade (G)3 neuroendocrine tumor (NET) distinct from neuroendocrine carcinoma (NEC), based on molecular differences and to triage the patients for appropriate therapy. This distinction largely relies on morphology, which can be challenging at times. Genomic profiling has revealed TP53andRB1mutations in NECs, while death domain-associated protein 6 (DAXX) and alpha-thalassemia/mental retardation X-linked (ATRX),in G3NET. Their role as biological markers in differentiating these entities and their significance as prognostic markers are not yet established. This study aims at analyzing the diagnostic and prognostic role of p53 and ATRX in neuroendocrine neoplasms of GIT and pancreas. A single-centre, eight-year retrospective study of neuroendocrine neoplasm of GIT and pancreas comprised G2NET, G3NET and NEC. Tumor slides were stained by immunohistochemistry for p53 and ATRX. Strong nuclear staining of > 50% of tumor cells for p53 was considered mutated. Nuclear staining of ATRX in < 5% of tumor cells was considered ATRX loss. Expression of p53 and ATRX was analyzed and correlated with tumor grades and patient survival. Fifty-five patients with gastro-entero-pancreatic neuroendocrine neoplasm were studied, comprising G2NET (58%), G3NET (16%) and NEC (26%). Median age of diagnosis was 59years with male predominance. The pancreas was the most common site followed by the small bowel. NEC showed lower survival compared to G3 and G2NET. Mutated p53 immunohistochemical expression was more frequent among NEC than G3NET. Patients with mutated p53 had significantly lower survival irrespective of the grade (p = 0.001). There was no association of ATRX loss with grade or survival. G3NETs are genetically different from NECs. Use of immunohistochemistry for p53 in addition to histomorphology may facilitate accurate categorization of NEC and G3NET. Mutated p53 may also be used as an independent prognostic marker in neuroendocrine tumors of GIT and pancreas.

Adipokines in Neuroendocrine Tumors: An Evaluation of the Serum Levels of Ghrelin and Leptin.

Neuroendocrine tumors (NETs) are a heterogeneous group of tumors that are characteristically different from other malignancies. The difference is not only in the prognosis, which is usually more favorable in such patients, but also in the high clinical progression of the disease, where NET patients do not experience the cachexia typical of other malignancies. The purposes of this study were to evaluate the ghrelin and leptin levels in a group of patients diagnosed with gastroenteropancreatic neuroendocrine tumors (GEP-NETs) and bronchopulmonary neuroendocrine tumors (BP-NETs) and to analyze the relationship between the body mass index (BMI), cachexia and selected NET markers. The study group comprised 52 patients with GEP-NETs and BP-NETs, while the controls comprised 67 healthy volunteers. The ghrelin and leptin concentrations were determined in both groups. The concentrations of chromogranin A, serotonin, 5-hydroxyindoleacetic acid (5-HIAA), total cholesterol, triglycerides and glucose were determined in the study group. Characteristics of the study group and of the controls were defined by age, sex and BMI, and the effects of these factors on the ghrelin and leptin concentrations were assessed. The data obtained were subject to statistical analysis. The study cohort showed higher levels of ghrelin as compared to the controls (142.31 ± 26.00 vs. 121.49 ± 35.45, p = 0.016), and no statistical difference in the levels of leptin (11.15 ± 9.6 vs. 12.94 ± 20.30, p = 0.439) were observed. Significantly lower levels of leptin were found in patients with the small intestine primary location, as compared to individuals with primary locations in the lungs and the pancreas (4.9 ± 6.49 vs. 16.97 ± 15.76, p = 0.045, and 4.9 ± 6.49 vs. 12.89 ± 8.56, p = 0.016, respectively). A positive correlation was observed between the leptin levels and the BMIs in both the study group (rS = 0.33, p = 0.016) and the controls (rS = 0.41, p = 0.001). The study group showed a negative correlation between the leptin levels and 5-HIAA (rS = -0.32, p = 0.026) and a negative correlation between the leptin levels and Ki-67 (rS = -0.33, p = 0.018). The control group showed negative correlations between the ghrelin and the volunteer age (rS = -0.41, p = 0.008), the leptin and the volunteer age (rS = -0.44, p < 0.001), the leptin and total cholesterol (rS = -0.24, p < 0.049) as well as the leptin and triglycerides (rS = -0.33, p < 0.006). The current study emphasized the importance of the markers' determination, where ghrelin appears as a valuable diagnostic biomarker in NETs, probably responsible for maintaining a normal BMI, despite the progression of the disease.

Serum concentrations of chromogranin A, serotonin and natriuretic peptide are decreased in patients with neuroendocrine tumors with overweight and obesity compared to healthy donors

Background: Neuroendocrine tumors (NETs) are a group of neoplasms, in which circulating biomarkers chromogranin A (CgA), serotonin, and N-terminal brain natriuretic pro-peptide (NT-proBNP), used as a marker of carcinoid heart disease, are especially important in the diagnosis and monitoring. A number of pre-analytical factors, including patients' body mass index (BMI), have an impact on NETs biomarker concentrations. Aim: To perform a comparative analysis of serum concentrations of CgA, serotonin and NT-proBNP in patients with NETs of various locations with normal body weight and with overweight or obesity. Methods: This cross-sectional study included 94 patients with NETs of various locations and 78 provisionally healthy individuals without cancer and cardiovascular disorders, matched by gender and age to the patients. Serum biochemical markers were measured before a course of chemotherapy/biotherapy or surgery with the use of standardized enzyme-linked immunosorbent assays Chromogranin A NEOELISA (Eurodiagnostica), Serotonin ELISA (IBL), and the electrochemiluminescent assay (Cobas e601 analyzer, Roche). All NETs patients were divided into 2 subgroups: 46 patients with normal bodyweight (BMI 18 to 24.9) and 48 patients with overweight/obesity (BMI ≥ 25). Results: The median BMI in the NET patients did not vary depending on their tumor extension, functional activity and malignancy grade. The median concentrations of CgA (150 ng/ml), serotonin (188 ng/ml) and NT-proBNP (117 pg/ml) in the NET patients with obesity and overweight were significantly lower (p = 0.008, p = 0.005 and p = 0.012, respectively) than in the NET patients with normal body weight (769 ng/ml, 704 ng/ml and 197 pg/ml, respectively). In the control group, significantly (p = 0.0001) lower levels in the subgroup with BMI ≥ 25 were obtained only for serotonin. The ROC analysis showed a decrease of the diagnostic efficiency of NET biomarkers in obesity: in the normal BMI group AUC (CgA) was 0.87 and AUC (serotonin) 0.78, whereas in those with BMI ≥ 25, the AUC (CgA) and AUC (serotonin) were 0.81 and 0.62, respectively. Conclusion: Obesity may make it difficult to identify biochemical markers of NETs – CgA, serotonin and NT-proBNP.

Neuroendocrine differentiation (ND) in sensitivity of neuroendocrine tumor (NET) cells to ONC201/TIC10 cancer therapeutic.

Prostate cancer (PCa) neuroendocrine tumor (NET)-like cells with low or absent androgen receptor (AR) signaling cause hormone therapy resistance and poor prognosis. Small cell lung carcinoma (SCLC), a high-grade NET, presents with metastasis early and has poor survival. ONC201/TIC10 is a first-in-class cancer therapeutic with clinical activity in diffuse gliomas and neuroendocrine tumors. We hypothesized that markers of neuroendocrine differentiation, activation of the integrated stress response (ISR) and the TRAIL pathway, as well as the expression of ClpP, contribute to neuroendocrine tumor cell death and sensitivity to ONC201. We show that PCa and SCLC cell lines (N=6) are sensitive to ONC201, regardless of the extent of neuroendocrine differentiation. Endogenous levels of some NET markers (CgA, FoxO1, ENO2, PGP9.5, SOX2) are present in a spectrum in PCa and SCLC cell lines. Overexpression of neural transcription factor BRN2 in DU145 PCa cells does not increase expression of NET differentiation markers FoxO1, ENO2, PGP9.5, and CgA at 48 hours. However, the transient BRN2 overexpression showed slight decreases in some NET markers on the spectrum while maintaining sensitivity of PCa cells to ONC201 before any phenotypic change related to NET differentiation. Our results show that ONC201 has preclinical activity against PCa including those without NET markers or in PCa cells with transient overexpression of neural transcription factor BRN2. Our results have relevance to activity of ONC201 in PCa where most castrate-resistant androgen-independent cancers are not therapy resistant due to NET differentiation. Importantly, NET differentiation does not promote resistance to ONC201 supporting further clinical investigations across the spectrum of PCa.

Gastroenteropancreatic neuroendocrine tumors: Epigenetic landscape and clinical implications

Neuroendocrine tumors (NETs) are a rare, heterogenous group of neoplasms arising from cells of the neuroendocrine system. Amongst solid tumor malignancies, NETs are notable for overall genetic stability and recent data supports the notion that epigenetic changes may drive NET pathogenesis. In this review, major epigenetic mechanisms of NET pathogenesis are reviewed, including changes in DNA methylation, histone modification, chromatin remodeling, and microRNA. Prognostic implications of the above are discussed, as well as the expanding diagnostic utility of epigenetic markers in NETs. Lastly, preclinical and clinical evaluations of epigenetically targeted therapies in NETs and are reviewed, with a focus on future directions in therapeutic advancement.

ENO2, a Glycolytic Enzyme, Contributes to Prostate Cancer Metastasis: A Systematic Review of Literature.

Prostate cancer (PCa) is the second leading cause of male cancer deaths in the UK and the fifth worldwide. The presence of distant PCa metastasis can reduce the 5-year survival rate from 100% to approximately 30%. Enolase 2 (ENO2), a crucial glycolytic enzyme in cancer metabolism, is associated with the metastasis of multiple cancers and is also used as a marker for neuroendocrine tumours. However, its role in PCa metastasis remains unclear. In this study, we systematically reviewed the current literature to determine the association between ENO2 and metastatic PCa. Medline, Web of Science, and PubMed were searched for eligible studies. The search yielded five studies assessing ENO2 expression in PCa patients or cell lines. The three human studies suggested that ENO2 expression is correlated with late-stage, aggressive PCa, including castrate-resistant PCa (CRPC), metastatic CRPC, and neuroendocrine PCa (NEPC). This was further supported by two in vitro studies indicating that ENO2 expression can be regulated by the tumour microenvironment, such as androgen deprived conditions and the presence of bone-forming osteoblasts. Therefore, ENO2 may functionally contribute to PCa metastasis, possibly due to the unique metabolic features of PCa, which are glycolysis dependent only at the advanced metastatic stage.

Biochemical Markers for Neuroendocrine Tumors: Traditional Circulating Markers and Recent Development—A Comprehensive Review

Neuroendocrine neoplasms (NENs) are a heterogeneous group of neoplasms presenting unique challenges in diagnosis and management. Traditional markers such as chromogranin A (CgA), pancreatic polypeptide (PP), and neuron-specific enolase (NSE) have limitations in terms of specificity and sensitivity. Specific circulating markers such as serotonin and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) and various gastrointestinal hormones such as gastrin, glucagon, somatostatin, and vasoactive intestinal peptide (VIP) have a role in identifying functional NENs. Recent advances in molecular and biochemical markers, also accounting for novel genomic and proteomic markers, have significantly improved the landscape for the diagnosis and monitoring of NENs. This review discusses these developments, focusing on both traditional markers such as CgA and NSE, as well as specific hormones like gastrin, insulin, somatostatin, glucagon, and VIP. Additionally, it covers emerging genomic and proteomic markers that are shaping current research. The clinical applicability of these markers is highlighted, and their role in improving diagnostic accuracy, predicting surgical outcomes, and monitoring response to treatment is demonstrated. The review also highlights the need for further research, including validation of these markers in larger studies, development of standardized assays, and integration with imaging techniques. The evolving field of biochemical markers holds promise for improving patient outcomes in the treatment of NENs, although challenges in standardization and validation remain.

A comparative study of INSM1 (clone MRQ70) immunoreactivity on CytoLyt® pretreated cytology and resection specimens of pancreatic neuroendocrine tumors.

Insulinoma-associated protein 1 (INSM1) is a newly characterized sensitive and specific immunohistochemical marker for neuroendocrine (NE) tumors. Whereas more traditional NE markers, such as chromogranin A and synaptophysin, are cytoplasmic, INSM1 is uniquely nuclear and thus could serve as a useful addition to NE tumor workup. While application of immunohistochemical studies to cytology specimens is becoming increasingly relevant, knowledge of the effects of the certain fixatives as well as the pattern and intensity of immunoexpression are important considerations. Sixteen cases of pancreatic neuroendocrine tumor (PanNET) diagnosed between 2015 and 2021 underwent both fine-needle aspiration, which was subsequently prepared in CytoLyt®-fixed cytology cell block (CCB), and surgical resection, in which specimens were prepared into formalin-fixed paraffin embedded blocks (FFPE). For all samples, INSM1 immunoreactivity was classified according to staining intensity and extent, then compared between CCBs and matched FFPEs. All 16 FFPE specimens demonstrated strong and diffuse INSM1 immunoreactivity, while only 10/16 (62.5%) CCBs were positive. Of those 10, only 2/10 (20%) demonstrated strong and diffuse reactivity. The choice of fixative has a demonstrable effect on the immunoreactivity of INSM1 in PanNET. Even though the sensitivity is lower in CytoLyt®-fixed cell block specimens, the addition of INSM1 is useful, especially in challenging cases that may be negative for one or more of the traditional NE markers.

Primary Cilia as a Tumor Marker in Pituitary Neuroendocrine Tumors

Pituitary neuroendocrine tumors (PitNETs) account for approximately 15% of all intracranial neoplasms. Although they usually appear to be benign, some tumors display worse behavior, displaying rapid growth, invasion, refractoriness to treatment, and recurrence. Increasing evidence supports the role of primary cilia (PC) in regulating cancer development. Here, we showed that PC are significantly increased in PitNETs and are associated with increased tumor invasion and recurrence. Serial electron micrographs of PITNETs demonstrated different ciliation phenotypes (dot-like versus normal-like cilia) that represented PC at different stages of ciliogenesis. Molecular findings demonstrated that 123 ciliary-associated genes (eg, doublecortin domain containing protein 2, Sintaxin-3, and centriolar coiled-coil protein 110) were dysregulated in PitNETs, representing the upregulation of markers at different stages of intracellular ciliogenesis. Our results demonstrate, for the first time, that ciliogenesis is increased in PitNETs, suggesting that this process might be used as a potential target for therapy in the future.

Single-Cell Transcriptome Analysis of Small Cell Neuroendocrine Carcinoma of the Endometrium Reveals ISL1 as a Potential Biomarker for Diagnosis and Treatment.

As a dedifferentiated tumor, small cell endometrial neuroendocrine tumors (NETs) are rare and frequently diagnosed at an advanced stage with a poor prognosis. Current treatment recommendations are often extrapolated from histologically similar tumors in other sites or based on retrospective studies. The exploration for diagnostic and therapeutic markers in small cell NETs is of great significance. In this study, we conducted single-cell RNA sequencing on a specimen obtained from a patient diagnosed with small cell endometrial neuroendocrine carcinoma (SCNEC) based on pathology. We revealed the cell map and intratumoral heterogeneity of the cancer cells through data analysis. Further, we validated the function of ISL LIM Homeobox 1 (ISL1) in vitro in an established neuroendocrine cell line. Finally, we examined the association between ISL1 and tumor staging in small cell lung cancer (SCLC) patient samples. We observed the significant upregulation of ISL1 expression in tumor cells that showed high expression of the neuroepithelial markers. Additionally, in vitro cell function experiments demonstrated that the high ISL1 expression group exhibited markedly higher cell proliferation and migration abilities compared to the low expression group. Finally, we showed that the expression level of ISL1 was correlated with SCLC stages. ISL1 protein in NETs shows promise as a potential biomarker for diagnosis and treatment.

SQSTM1/p62 is a prognostic molecular marker and potential therapeutic target for pancreatic neuroendocrine tumours.

There have been few studies on the role of autophagy in pancreatic neuroendocrine tumours (PNETs). SQSTM1/p62 (also called Sequestosome 1) is a potential autophagy regulator, and its biological roles and clinical significance in PNETs remain poorly understood. The purpose of this study was to evaluate the clinical significance of SQSTM1/p62 in human PNET specimens and to evaluate its potential value as a therapeutic target by studying its biological function in PNET cell lines. SQSTM1/p62 protein expression was assessed in 106 PNET patient specimens by immunohistochemistry, and the relationship between SQSTM1/p62 protein expression and the clinicopathological features of PNETs in patients was analysed. The proliferation, invasion and apoptosis of SQSTM1/p62-knockdown QGP-1 and INS-1 cells were assessed by the MTT assay, a Transwell assay and flow cytometry. Cell autophagy was assessed by western blotting and mCherry-GFP-LC3B. The protein expression of SQSTM1/p62 in PNET patient specimens was significantly correlated with tumour recurrence (p = 0.005) and worse prognosis (log rank p = 0.020). Downregulation of the SQSTM1/p62 gene inhibited tumour cell proliferation and migration and induced PNET cell death. Downregulation of SQSTM1/p62 activated autophagy in PNET cell lines but blocked autophagic flow. Knockdown of the SQSTM1/p62 gene inhibited mTOR phosphorylation. The SQSTM1/P62 protein could be an independent prognostic marker for PNET patients. Downregulating SQSTM1/P62 can inhibit PNET progression, inhibit mTOR phosphorylation and block autophagic flow.

PITX2 as a Sensitive and Specific Marker of Midgut Neuroendocrine Tumors: Results from a Cohort of 1157 Primary Neuroendocrine Neoplasms

As neuroendocrine tumors (NETs) often present as metastatic lesions, immunohistochemical assignment to a site of origin is one of the most important tasks in their pathologic assessment. Because a fraction of NETs eludes the typical expression profiles of their primary localization, additional sensitive and specific markers are required to improve diagnostic certainty.We investigated the expression of the transcription factor Pituitary Homeobox 2 (PITX2) in a large-scale cohort of 909 NET and 248 neuroendocrine carcinomas (NEC) according to the immunoreactive score (IRS) and correlated PITX2 expression groups with general tumor groups and primary localization.PITX2 expression (all expression groups) was highly sensitive (98.1%) for midgut-derived NET, but not perfectly specific, as non–midgut NET (especially pulmonary/duodenal) were quite frequently weak or moderately positive. The specificity rose to 99.5% for a midgut origin of NET if only a strong PITX2 expression was considered, which was found in only 0.5% (one pancreatic/one pulmonary) of non–midgut NET. In metastases of midgut-derived NET, PITX2 was expressed in all cases (87.5% strong, 12.5% moderate), whereas CDX2 was negative or only weakly expressed in 31.3% of the metastases. In NEC, a fraction of cases (14%) showed a weak or moderate PITX2 expression, which was not associated with a specific tumor localization.Our study independently validates PITX2 as a very sensitive and specific immunohistochemical marker of midgut-derived NET in a very large collective of neuroendocrine neoplasms. Therefore, our data argue toward implementation into diagnostic panels applied for NET as a firstline midgut marker.

Abstract B009: Identifying of a novel diagnostic markers for pancreatic neuroendocrine tumors by proteomics with patient blood

Abstract Neuroendocrine tumors are tumors originating from endocrine cells in various organs, and present very heterogeneous characteristics, and the incidence rate is gradually increasing. Among them, neuroendocrine tumors originating from pancreas are divided into functional tumors and non-functional tumors according to the presence hormone secretion function. Since non-functional tumors are often asymptomatic, early diagnosis is not easy, and differential diagnosis from pancreas ductal adenocarcinoma (PDAC) is difficult, making it difficult to determine the direction of treatment. Therefore, we aimed to find protein biomarkers for the diagnosis and differential diagnosis of pancreatic neuroendocrine tumors (PNET) through proteomic analysis of human blood. First, a total of 60 human plasma samples were obtained from 17 PNETs, 23 PDACs, and 20 Healthy donors (HD), and liquid chromatography-mass spectrometry (LC-MS) proteomics analysis was performed. For 60 cases of raw data obtained through LC-MS analysis, identification and label-free quantification were performed through the Human swissprot protein sequence database. Through pre-processing and normalization, an average of 549 protein lists for each sample were obtained. And through quantitative evaluation, the proteomes that were increased or decreased for each disease were analyzed and classified, and ACTR3, CD163, and LECT2, which were increased in PNET, were selected as diagnostic biomarker candidates. The diagnostic AUC for distinguishing PNET from HD was 0.706 for ACTR3, 0.971 for CD163, and 0.541 for LECT2. The diagnostic AUC to distinguish PNET from PDAC was 0.821 for ACTR3, 0.870 for CD163, and 0.783 for LECT2. We selected three candidates, ACTR3, CD163, and LECT2, as blood biomarkers for the accurate diagnosis of PNET. And through the combination of markers, it is expected that the sensitivity and accuracy of the diagnosis can be further increased. In the future, we will study the function as a marker that can simultaneously predict diagnosis and treatment response by identifying the molecular biological mechanism for the generation and progression of PNET through these three markers. Citation Format: Eun-Young Koh, Ji Hye Jeong, Hee-Sung Ahn, Kyunggon Kim, Eunsung Jun. Identifying of a novel diagnostic markers for pancreatic neuroendocrine tumors by proteomics with patient blood [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr B009.

Significance of Chromogranin A and Synaptophysin in Gastroenteropancreatic Neuroendocrine Tumors

The two most commonly used immunohistochemical markers for neuroendocrine tumors are chromogranin A and synaptophysin. We had previously studied immunohistochemical staining on pancreatic neuroendocrine tumors: chromogranin A strongly positive tumors including gastrinomas, glucagonomas, pancreatic polypeptidomas were more malignant (&gt;50%) than chromogranin A weakly positive tumors of insulinomas (&lt;10%). With additional 40 cases of gastroenteric neuroendocrine tumors, formerly carcinoid tumors, we investigated chromogranin A and synaptophysin immunostaining: more aggressive neuroendocrine tumors of duodenum, small intestine and ascending colon were strongly positive for chromogranin compared to less aggressive neuroendocrine tumors of sigmoid colon and rectum. Immunohistochemical staining for chromogranin A represents a marker for the secretary granules with a possible marker of prognosis on all gastroenteropancreatic neuroendocrine tumors. Furthermore, serum CgA levels may be used as an indirect, independent diagnostic and prognostic marker for gastroenteropa-ncreatic neuroendocrine tumors in three folds: First to diagnose gastroenteropancreatic neuroendocrine tumors. Secondly, to assess the degree of malignancy by tissue and serum CgA levels and thirdly, evaluate increasing serum CgA levels as a prognostic indicator. Since there is no difference of immunostaining for synaptophysin between more aggressive neuroendocrine tumors and less aggressive tumors, immunostaining for synaptophysin is not a marker for aggressive tumors.

Plasma or serum 5-hydroxyindoleacetic acid can be used interchangeably in patients with neuroendocrine tumours

5-hydroxyindole acetic acid, a metabolite of serotonin, is used in the diagnosis and monitoring of patients with neuroendocrine tumours, in particular patients with small intestinal neuroendocrine tumours associated with the carcinoid syndrome. Analysis of 5-hydroxyindole acetic acid was commonly performed in urine, but blood-based assays are now becoming available. The objective of this study was to assess how 5-hydroxyindole acetic acid compares in plasma and serum as a biochemical marker of neuroendocrine tumours. Twenty-four-hour urine, plasma and serum samples were obtained from 80 patients with neuroendocrine tumours and 30 healthy volunteers. We developed a liquid chromatography tandem mass spectrometry assay for plasma and serum 5-hydroxyindole acetic acid. Comparison was made between them, and their cut-off was determined using a receiver-operating characteristic curve. A close correlation was shown between plasma and serum 5-hydroxyindole acetic acid. At a cut-off of 135 nmol/l, a sensitivity of 91.2% with a specificity of 61.9% was obtained for both compared to the urinary assay. A statistically significant agreement was shown when plasma and serum 5-hydroxyindole acetic acid were compared with the currently used urine assay in patients with neuroendocrine tumours; κ = 0.675 (95% CI 0.49 to 0.86), p < 0.001 and healthy volunteers; 0.967 (95% CI 0.828 to 0.999), p = <0.001. In conclusion, 5-hydroxyindole acetic acid in plasma and serum were comparable, hence either sample type can be used interchangeably.

176P Identification of novel diagnostic markers for pancreatic neuroendocrine tumors by proteomics with patient blood

176P Identification of novel diagnostic markers for pancreatic neuroendocrine tumors by proteomics with patient blood

FLNA expression modulates pathological markers of pituitary neuroendocrine tumours.

Due to the current limited knowledge about the role of filamin A (FLNA) in pituitary tumour progression, we aimed to analyse FLNA expression levels and its impact on aggressive markers of pituitary neuroendocrine tumours (PitNETs), using an integrative approach of in vivo and in vitro models and human samples. An increase in the expression levels of FLNA was observed in the advanced tumoural stages of the hyperplastic adenomatous pituitary model, concomitant with a decrease in cell proliferation and with a modification in the subcellular localisation of this protein. Similarly, overexpression of FLNA in the somatolactotropic GH3 cell line induced a decrease in the cell proliferation, promoted a migratory phenotype, increased invasion activity, and decreased the prolactin secretion. Cyclin D1 (CCND1) and cyclin-dependent kinase 4 (CDK4) expression increased in both models in correlation with the increase observed in FLNA levels. When human tissues were analysed a significant increase of FLNA was observed in PitNETs compared to normal pituitary gland, with heterogeneous intracellular localisation. Higher levels of FLNA expression were observed in tumours with invasive characteristics. These results underline the crucial roles of FLNA as a modulator of pathological markers and as a potential prognostic marker in pituitary tumours.

Correlation between clinicopathological characteristics and the clinical prognosis of patients with gastroenteropancreatic neuroendocrine tumors.

Gastroenteropancreatic (GEP) neuroendocrine tumors (NETs) are one of the most common types of NETs, accounting for 65-75% of all NETs. However, epidemiological characteristics of patients with GEP-NETs in China are still lacking. The present retrospective study aimed to investigate the local epidemiology of GEP-NETs and assess the prognostic factors in China. The data of 267 patients with GEP-NETs who were admitted to the First Affiliated Hospital of Bengbu Medical College (Bengbu, China) and the Affiliated Hospital of West Anhui Health Vocational College (Lu'an, China) were retrospectively reviewed. The clinical and pathological characteristics of the patients, as well as follow-up information, were collected, and the 5-year survival rate was calculated. Kaplan-Meier curves and log-rank analysis were used to analyze the prognostic factors. The stomach (100/267; 37.5%) was the most common site of GEP-NETs and the liver (25/39; 64.1%) was the most common metastatic site. A total of 166 (62.2%) and 219 (82.0%) patients had positive results for chromogranin A (CgA) and synaptophysin (Syn), respectively. The percentage of patients with tumor grade G1, G2 and G3 was 33.3, 21.0 and 45.7%, respectively. The 5-year overall survival rate was 79.7%, and the age, tumor site, distant metastasis and tumor grading upon diagnosis were all prognostic factors. In conclusion, the present case series investigated the epidemiology and prognostic factors of GEP-NETs in China. CgA and Syn could be used as diagnostic markers for NETs and the stomach was the most common primary tumor site. Lymph node metastasis, tumor site, distant metastasis and tumor grading were important prognostic factors.

Immunoreactivity of HOXB13 in Neuroendocrine Neoplasms Is a Sensitive and Specific Marker of Rectal Well-Differentiated Neuroendocrine Tumors.

HoxB13 is a transcription factor involved in defining of posterior endodermal derivatives, including prostate and rectum. While it is used as a marker of prostatic adenocarcinoma, it has not been studied systematically in neuroendocrine neoplasms. Thus, we performed HoxB13 immunohistochemistry in tissue microarrays and the whole sections of 232 neuroendocrine neoplasms. These included 34 paragangliomas (PGs), 20 cauda equina neuroendocrine tumors (CENETs), 123 well-differentiated neuroendocrine tumors (WDNETs), and 55 neuroendocrine carcinomas (NECs). WDNETs were additionally analyzed with SATB2, and colorectal WDNETs with CDX2 and serotonin immunohistochemistry. In total, HoxB13 immunoreactivity was observed in 95% (19/20) CENETs, 10.6% (13/123) WDNETs, and 12.9% (7/54) NECs. No PGs were positive. Large intestine WDNETs expressed HoxB13 in 68.4% (13/19); five negative tumors originated in cecum and one in rectum. In rectum, 92.9% (13/14) WDNETs expressed HoxB13. HoxB13 was 92.9% sensitive and 100% specific, showing 100% positive predictive value for the rectal origin of WDNET. In NECs, HoxB13 was positive in 15.4% (2/13) GIT tumors and 80% (4/5) prostatic NECs, but in none of urinary bladder NECs (0/8). SATB2 was positive in 17.1% (21/123) WDNETs, including 78.9% (15/19) of colorectal WDNETs, 71.4% (5/7) appendiceal WDNETs, and 2.9% (1/34) small intestine WDNETs. All 4 SATB2-negative large bowel tumors originated in the cecum. When both markers combined, HoxB13+/SATB2+ immunoprofile was seen exclusively in rectal WDNETs (positive predictive value 100%), while HoxB13-/SATB2+ immunoprofile was highly suggestive of the appendiceal origin (positive predictive value 71.4%). Therefore, HoxB13 can be useful as an immunohistochemical marker of rectal WDNETs and prostatic NECs.