Plasma protein biomarkers for the detection of pancreatic neuroendocrine tumors and differentiation from small intestinal neuroendocrine tumors

There is an unmet need for novel biomarkers to diagnose and monitor patients with neuroendocrine neoplasms. The EXPLAIN study explores a multi-plasma protein and supervised machine learning strategy to improve the diagnosis of pancreatic neuroendocrine tumors (PanNET) and differentiate them from small intestinal neuroendocrine tumors (SI-NET). At time of diagnosis, blood samples were collected and analyzed from 39 patients with PanNET, 135 with SI-NET (World Health Organization Grade 1-2) and 144 controls. Exclusion criteria were other malignant diseases, chronic inflammatory diseases, reduced kidney or liver function. Prosed Oncology-II (i.e., OLink) was used to measure 92 cancer related plasma proteins. Chromogranin A was analyzed separately. Median age in all groups was 65-67 years and with a similar sex distribution (females: PanNET, 51%; SI-NET, 42%; controls, 42%). Tumor grade (G1/G2): PanNET, 39/61%; SI-NET, 46/54%. Patients with liver metastases: PanNET, 78%; SI-NET, 63%. The classification model of PanNET versus controls provided a sensitivity (SEN) of 0.84, specificity (SPE) 0.98, positive predictive value (PPV) of 0.92 and negative predictive value (NPV) of 0.95, and area under the receiver operating characteristic curve (AUROC) of 0.99; the model for the discrimination of PanNET versus SI-NET providing a SEN 0.61, SPE 0.96, PPV 0.83, NPV 0.90 and AUROC 0.98. These results suggest that a multi-plasma protein strategy can significantly improve diagnostic accuracy of PanNET and SI-NET.Peer reviewe

Intravenous versus oral etoposide : efficacy and correlation to clinical outcome in patients with high-grade metastatic gastroenteropancreatic neuroendocrine neoplasms (WHO G3)

High-grade gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs, G3) are aggressive cancers of the digestive system with poor prognosis and survival. Platinum-based chemotherapy (cisplatin/carboplatin + etoposide) is considered the first-line palliative treatment. Etoposide is frequently administered intravenously; however, oral etoposide may be used as an alternative. Concerns for oral etoposide include decreased bioavailability, inter-and intra-patient variability and patient compliance. We aimed to evaluate possible differences in progression-free survival (PFS) and overall survival (OS) in patients treated with oral etoposide compared to etoposide given as infusion. Patients (n = 236) from the Nordic NEC study were divided into three groups receiving etoposide as a long infusion (24 h, n = 170), short infusion (= 5 h, n = 33) or oral etoposide (n = 33) according to hospital tradition. PFS and OS were analyzed with Kaplan-Meier (log-rank), cox proportional hazard ratios and confidence intervals. No statistical differences were observed in PFS or OS when comparing patients receiving long infusion (median PFS 3.8 months, median OS 14.5 months), short infusion (PFS 5.6 months, OS 11.0 months) or oral etoposide (PFS 5.4 months, OS 11.3 months). We observed equal efficacy for the three administration routes suggesting oral etoposide may be safe and efficient in treating high-grade GEP-NEN, G3 patients scheduled for cisplatin/carboplatin + etoposide therapy.Peer reviewe

European Neuroendocrine Tumor Society 2023 guidance paper for functioning pancreatic neuroendocrine tumour syndromes.

This ENETS guidance paper aims to provide practical advice to clinicians for the diagnosis, treatment and follow-up of functioning syndromes in pancreatic neuroendocrine tumours (NET). A NET-associated functioning syndrome is defined by the presence of a clinical syndrome combined with biochemical evidence of inappropriately elevated hormonal levels. Different hormonal syndromes can be encountered in pancreatic NET patients, including insulinoma, gastrinoma as well as the rare glucagonoma, VIPoma, ACTHoma, PTHrPoma, carcinoid syndrome, calcitoninoma, GHRHoma and somatostatinoma. The recommendations provided in this paper focus on the biochemical, genetic and imaging work-up as well as therapeutic management of the individual hormonal syndromes in well-differentiated, grade 1-3, functioning NET with the primary tumour originating in the pancreas, and for specific subtypes also in the duodenum

Expression of p53 protein in high-grade gastroenteropancreatic neuroendocrine carcinoma

Background Gastroenteropancreatic neuroendocrine carcinomas (GEP-NECs) are aggressive, rapidly proliferating tumors. Therapeutic response to current chemotherapy regimens is usually short lasting. The aim of this study was to examine the expression and potential clinical importance of immunoreactive p53 protein in GEP-NEC. Materials and methods Tumor tissues from 124 GEP-NEC patients with locally advanced or metastatic disease treated with platinum-based chemotherapy were collected from Nordic centers and clinical data were obtained from the Nordic NEC register. Tumor proliferation rate and differentiation were re-evaluated. All specimens were immunostained for p53 protein using a commercially available monoclonal antibody. Kaplan-Meier curves and cox regression analyses were used to assess progression-free survival (PFS) and overall survival (OS). Results All tumor tissues were immunoreactive for either one or both neuroendocrine biomarkers (chromogranin A and synaptophysin) and Ki67 index was >20% in all cases. p53 immunoreactivity was only shown in 39% of the cases and was not found to be a prognostic marker for the whole cohort. However, p53 immunoreactivity was correlated with shorter PFS in patients with colorectal tumors (HR = 2.1, p = 0.03) in a univariate analysis as well as to poorer PFS (HR = 2.6, p = 0.03) and OS (HR = 3.4, p = 0.02) in patients with colorectal tumors with distant metastases, a correlation which remained significant in the multivariate analyses. Conclusion In this cohort of GEP-NEC patients, p53 expression could not be correlated with clinical outcome. However, in patients with colorectal NECs, p53 expression was correlated with shorter PFS and OS. Further studies are needed to establish the role of immunoreactive p53 as a prognostic marker for GEP-NEC patients.Peer reviewe

ENETS Consensus Guidelines for the Standards of Care in Neuroendocrine Tumors: Pathology: Diagnosis and Prognostic Stratification.

The European Neuroendocrine Tumor Society (ENETS) proposed standard of care guidelines for pathology in 2009. Since then, profound changes in the classification have been made, dividing neuroendocrine neoplasia (NEN) into well-differentiated neuroendocrine tumors (NET) and poorly differentiated neuroendocrine carcinomas (NEC) in the 2010 WHO classification. The 7th edition of the TNM classification (2009) included NEN for the first time, widely adapting ENETS proposals but with some differences for NEC and for NET of the pancreas and the appendix. Therapy guidelines for gastroenteropancreatic NET were updated in 2016. The need for an update of the standards of care prompted the ENETS to organize a consensus conference which was held in Antibes in 2015; a working group was designated to propose pathological standards of car

Pan-Pathway Based Interaction Profiling of FDA-Approved Nucleoside and Nucleobase Analogs with Enzymes of the Human Nucleotide Metabolism

To identify interactions a nucleoside analog library (NAL) consisting of 45 FDA-approved nucleoside analogs was screened against 23 enzymes of the human nucleotide metabolism using a thermal shift assay. The method was validated with deoxycytidine kinase; eight interactions known from the literature were detected and five additional interactions were revealed after the addition of ATP, the second substrate. The NAL screening gave relatively few significant hits, supporting a low rate of “off target effects.” However, unexpected ligands were identified for two catabolic enzymes guanine deaminase (GDA) and uridine phosphorylase 1 (UPP1). An acyclic guanosine prodrug analog, valaciclovir, was shown to stabilize GDA to the same degree as the natural substrate, guanine, with a ΔTagg around 7°C. Aciclovir, penciclovir, ganciclovir, thioguanine and mercaptopurine were also identified as ligands for GDA. The crystal structure of GDA with valaciclovir bound in the active site was determined, revealing the binding of the long unbranched chain of valaciclovir in the active site of the enzyme. Several ligands were identified for UPP1: vidarabine, an antiviral nucleoside analog, as well as trifluridine, idoxuridine, floxuridine, zidovudine, telbivudine, fluorouracil and thioguanine caused concentration-dependent stabilization of UPP1. A kinetic study of UPP1 with vidarabine revealed that vidarabine was a mixed-type competitive inhibitor with the natural substrate uridine. The unexpected ligands identified for UPP1 and GDA imply further metabolic consequences for these nucleoside analogs, which could also serve as a starting point for future drug design

Preventive medicine of von Hippel-Lindau disease-associated pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PanNETs) are rare in von Hippel-Lindau disease (VHL) but cause serious morbidity and mortality. Management guidelines for VHL-PanNETs continue to be based on limited evidence, and survival data to guide surgical management are lacking. We established the European-American-Asian-VHL-PanNET-Registry to assess data for risks for metastases, survival and long-term outcomes to provide best management recommendations. Of 2330 VHL patients, 273 had a total of 484 PanNETs. Median age at diagnosis of PanNET was 35 years (range 10-75). Fifty-five (20%) patients had metastatic PanNETs. Metastatic PanNETs were significantly larger (median size 5 vs 2\u2009cm; P\u20091.5\u2009cm in diameter were operated. Ten-year survival was significantly longer in operated vs non-operated patients, in particular for PanNETs <2.8\u2009cm vs 652.8\u2009cm (94% vs 85% by 10 years; P\u2009=\u20090.020; 80% vs 50% at 10 years; P\u2009=\u20090.030). This study demonstrates that patients with PanNET approaching the cut-off diameter of 2.8\u2009cm should be operated. Mutations in exon 3, especially of codons 161/167 are at enhanced risk for metastatic PanNETs. Survival is significantly longer in operated non-metastatic VHL-PanNETs

Midgut Carcinoid Tumours : New Diagnostic Procedures and Treatment

Midgut carcinoid tumours are rare with an incidence of 0.5-2.1/100 000. The primary tumour is usually small and grows slowly but has almost always set metastases at diagnosis. When radically operated, most patients will eventually recur in their disease. We evaluated different methods in detecting recurrent disease in 61 malignant midgut carcinoid tumours that had been radically operated. Thirty-eight patients have been diagnosed with a recurrence. In 32/38 of these patients P-Chromogranin A was the first method to indicate a recurrence. We therefore recommend using P-CgA in the work up in these patients. We investigated characteristics, survival and independent factors that could be of bad prognostic value. We found that in our 284 malignant midgut carcinoid tumours, 208/284 (73%) had distant metastases and 30/284 (11%) had carcinoid heart disease. Median survival was 115.5 months and five-year survival was 77%. In a multivariate analysis liver metastases and carcinoid heart disease were poor prognostic factors. We performed a phase II study with octreotide pamoate investigating the clinical effect in 12 malignant midgut carcinoid tumours in a progressive phase. We found that 9/12 (75%) were stabilised for a median duration of 12 months. We think that this is a good effect considering the advanced stage. We investigated the frequency of four different tyrosine kinase receptors, platelet derived growth factor receptor (PDGR) α and β, epidermal growth factor receptor (EGFR) and c-kit, in 36 malignant midgut carcinoid tumours with immunohistochemistry. We found that 13/34 (38%) tumour samples expressed PDGFRα, 29/33 (88%) PDGFRβ, 24/33 (73%) EGFR, whereas none expressed c-kit. This implicates that midgut carcinoid tumours might be susceptible to treatment with tyrosine kinase receptor inhibitors

Midgut Carcinoid Tumours : New Diagnostic Procedures and Treatment

Midgut carcinoid tumours are rare with an incidence of 0.5-2.1/100 000. The primary tumour is usually small and grows slowly but has almost always set metastases at diagnosis. When radically operated, most patients will eventually recur in their disease. We evaluated different methods in detecting recurrent disease in 61 malignant midgut carcinoid tumours that had been radically operated. Thirty-eight patients have been diagnosed with a recurrence. In 32/38 of these patients P-Chromogranin A was the first method to indicate a recurrence. We therefore recommend using P-CgA in the work up in these patients. We investigated characteristics, survival and independent factors that could be of bad prognostic value. We found that in our 284 malignant midgut carcinoid tumours, 208/284 (73%) had distant metastases and 30/284 (11%) had carcinoid heart disease. Median survival was 115.5 months and five-year survival was 77%. In a multivariate analysis liver metastases and carcinoid heart disease were poor prognostic factors. We performed a phase II study with octreotide pamoate investigating the clinical effect in 12 malignant midgut carcinoid tumours in a progressive phase. We found that 9/12 (75%) were stabilised for a median duration of 12 months. We think that this is a good effect considering the advanced stage. We investigated the frequency of four different tyrosine kinase receptors, platelet derived growth factor receptor (PDGR) α and β, epidermal growth factor receptor (EGFR) and c-kit, in 36 malignant midgut carcinoid tumours with immunohistochemistry. We found that 13/34 (38%) tumour samples expressed PDGFRα, 29/33 (88%) PDGFRβ, 24/33 (73%) EGFR, whereas none expressed c-kit. This implicates that midgut carcinoid tumours might be susceptible to treatment with tyrosine kinase receptor inhibitors

Midgut Carcinoid Tumours : New Diagnostic Procedures and Treatment

Midgut carcinoid tumours are rare with an incidence of 0.5-2.1/100 000. The primary tumour is usually small and grows slowly but has almost always set metastases at diagnosis. When radically operated, most patients will eventually recur in their disease. We evaluated different methods in detecting recurrent disease in 61 malignant midgut carcinoid tumours that had been radically operated. Thirty-eight patients have been diagnosed with a recurrence. In 32/38 of these patients P-Chromogranin A was the first method to indicate a recurrence. We therefore recommend using P-CgA in the work up in these patients. We investigated characteristics, survival and independent factors that could be of bad prognostic value. We found that in our 284 malignant midgut carcinoid tumours, 208/284 (73%) had distant metastases and 30/284 (11%) had carcinoid heart disease. Median survival was 115.5 months and five-year survival was 77%. In a multivariate analysis liver metastases and carcinoid heart disease were poor prognostic factors. We performed a phase II study with octreotide pamoate investigating the clinical effect in 12 malignant midgut carcinoid tumours in a progressive phase. We found that 9/12 (75%) were stabilised for a median duration of 12 months. We think that this is a good effect considering the advanced stage. We investigated the frequency of four different tyrosine kinase receptors, platelet derived growth factor receptor (PDGR) α and β, epidermal growth factor receptor (EGFR) and c-kit, in 36 malignant midgut carcinoid tumours with immunohistochemistry. We found that 13/34 (38%) tumour samples expressed PDGFRα, 29/33 (88%) PDGFRβ, 24/33 (73%) EGFR, whereas none expressed c-kit. This implicates that midgut carcinoid tumours might be susceptible to treatment with tyrosine kinase receptor inhibitors