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Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) may occur in 30% to 90% of patients with multiple endocrine neoplasia type 1 (MEN1). However, only 1% of GEP-NETs are grade 3 (G3). Given the rarity of these aggressive tumors, treatment of advanced G3 GEP-NETs in MEN1 is based on the treatment guidelines for sporadic GEP-NETs. We report a 43-year-old male with germline MEN1 followed at our institution, with clinical features including hyperparathyroidism, a nonfunctional pancreatic NET, and Zollinger–Ellison syndrome. On routine surveillance imaging at age 40, computed tomography/positron emission tomography imaging showed 2 arterially enhancing intraluminal masses on the medial aspect of the gastric wall. Anatomical imaging confirmed 2 enhancing masses within the pancreas and a rounded mass-like thickening along the lesser curvature of the stomach. The gastric mass was resected, and pathology reported a well-differentiated G3 NET with a Ki-67 >20%. The patient continued active surveillance. Eighteen months later cross-sectional imaging studies showed findings consistent with metastatic disease within the right hepatic lobe and bland embolization was done. On follow-up scans, including 68Ga-DOTATATE (68Ga-DOTA(0)-Tyr(3)-octreotate) imaging, interval increase in number and avidity of metastatic lesions were compatible with disease progression. Given a paucity of treatment recommendations for G3 tumors in MEN1, the patient was counseled based on standard NET treatment guidelines and recommended 177Lu-DOTATATE treatment. PRRT (peptide receptor radionuclide therapy) with 177Lu-DOTATATE (177Lu-tetraazacyclododecanetetraacetic acid-octreotide) is an important therapeutic modality for patients with somatostatin receptor–positive NETs. However, prospective studies are needed to understand the role of PRRT in G3 NETs.

Purpose To compare the deoxyribonucleic acid (DNA) methylation signature of neuroendocrine tumors (NETs) by primary tumor site and inherited predisposition syndromes von Hippel–Lindau disease (VHL) and multiple endocrine neoplasia type 1 (MEN1). Methods Genome-wide DNA methylation (835 424 CpGs) of 96 NET samples. Principal components analysis (PCA) and unsupervised hierarchical clustering analyses were used to determine DNA methylome signatures. Results Hypomethylated CpGs were significantly more common in VHL-related versus sporadic and MEN1-related NETs (P < .001 for both comparisons). Small-intestinal NETs (SINETs) had the most differentially methylated CpGs, either hyper- or hypomethylated, followed by duodenal NETs (DNETs) and pancreatic NETs (PNETs, P < .001 for all comparisons). There was complete separation of SINETs on PCA, and 3 NETs of unknown origin clustered with the SINET samples. Sporadic, VHL-related, and MEN1-related PNETs formed distinct groups on PCA, and VHL clustered separately, showing pronounced DNA hypomethylation, while sporadic and MEN1-related NETs clustered together. MEN1-related PNETs, DNETs, and gastric NETs each had a distinct DNA methylome signature, with complete separation by PCA and unsupervised clustering. Finally, we identified 12 hypermethylated CpGs in the 1A promoter of the APC (adenomatous polyposis coli) gene, with higher methylation levels in MEN1-related NETs versus VHL-related and sporadic NETs (P < .001 for both comparisons). Conclusions DNA CpG methylation profiles are unique in different primary NET types even when occurring in MEN1-related NETs. This tumor DNA methylome signature may be utilized for noninvasive molecular characterization of NETs, through DNA methylation profiling of biopsy samples or even circulating tumor DNA in the near future.

Objective There is scant data of the genome-wide methylome alterations in neuroendocrine tumors (NET). Thus, the goal of this study was to compare the DNA methylation signature of NETs with respect to various primary sites and inherited genetic predisposition syndromes including von Hippel-Lindau (VHL) and multiple endocrine neoplasia type 1 (MEN1). Methods Genome-wide DNA methylation analysis of 96 NETs (primary and metastatic) was performed by using the Illumina Infinium EPIC Array. Principal component analysis (PCA) and unsupervised clustering analyses were performed to identify distinct methylome signatures. The methylation status of genetic drivers such as APC were assessed by primary site. Results A total of 835,424 CpGs methylation sites were quantified. Hypermethylated CpG sites were detected more frequently in sporadic vs. MEN1-related vs. VHL-related NETs, respectively (p < 0.001 for all comparisons), while hypomethylated CpGs sites were more common in VHL-related NETs vs. sporadic and MEN1-related NETs (p Small-intestinal NETs (SINETs) had the most differences at CpGs with the highest number of hyper- and hypomethylated CpG sites, followed by duodenal NETs (DNETs) and pancreatic NETs (PNETs, p Conclusion Various primary NET sites and genetically predisposed MEN1-related NETs have distinct DNA CpG methylation signatures. The methylome signatures identified in this study may be useful for non-invasive molecular characterization of NETs, through DNA methylation profiling of biopsy samples or circulating tumor DNA.

Background: Here we describe a patient who presented with symptomatic hypocalcemia and a biochemical picture suggestive of PTH resistance. PTH resistance is a hallmark of pseudohypoparathyroidism, a heterogeneous group of rare disorders caused by genetic or epigenetic alterations of PTH/PTHrP signaling. However, PTH receptor-related autoimmune etiology has not been identified as the underlying mechanism for PTH resistance. Here we describe the first case of acquired autoimmune PTH resistance that is secondary to PTH1R autoantibodies. Clinical Case: A 60-year-old African-American woman, who previously had normal calcium homeostasis, presented with acute, symptomatic hypocalcemia, hyperphosphatemia and markedly elevated serum PTH, consistent with parathyroid hormone resistance. She did not have other hormone resistance or a clinical phenotype suggestive of pseudohypoparathyroidism. Whole-exome sequencing and GNAS methylation analysis revealed no genetic or epigenetic defects of the PTH/PTHrP signaling pathway. Treatment with Calcitriol and Calcium supplements was initiated with good clinical response. Within 10 years of follow-up, the patient developed autoimmune hypothyroidism, alopecia and an unusual form of membranous glomerulonephritis, raising the suspicion for an autoimmune etiology for PTH resistance. Luciferase immunoprecipitation system assay identified antibodies against PTH1R with mapping to the N-terminal extracellular ligand-binding domain (amino acids 1- 178). Using an in vitro biological assay in GP-2.3 cells, we found that the antibodies derived from the patient’s serum blocked PTH downstream signaling via Gsalpha/cAMP/protein kinase A pathway in a concentration-dependent manner. The patient’s autoantibody profile led to the diagnosis of additional autoimmune diseases, including atrophic gastritis and Sjogren syndrome. Lymphocyte immunophenotyping using flow cytometry revealed an overall normal B and T cell profile, but with decreased frequencies and numbers of switched and non-switched memory B cell subsets and an increased frequency and number of the CD8+ naïve cell population. Genes associated with autoimmune inflammatory disorders were sequenced but no pathologic changes were detected. Conclusions: Identification of the first case of autoimmune PTH resistance secondary to PTH1R autoantibodies extends the etiologic spectrum of hypoparathyroidism and should be considered when a patient presents with findings consistent with pseudohypoparathyroidism, especially in the presence of additional autoimmune diseases.

Background: Neuroendocrine neoplasms (NEN) are a heterogenous group of tumors. Patients with the multiple endocrine neoplasia type 1 (MEN1) syndrome often manifest with simultaneous functional and non-functional NEN in various endocrine glands. In MEN1, nuclear medicine plays an important role in the diagnostic work-up and localization of NEN. Little is known about the comparative efficacy of 68Ga-Dotatate PET/CT (DOTA) versus 18F-FDOPA PET/CT (FDOPA) and both versus non-nuclear medicine imaging (CT and MRI) in the identification of primary and metastatic NEN. Methods: This prospective MEN1 cohort study evaluated 15 germline MEN1 mutation-positive patients. Subjects were imaged using CT, MRI, DOTA and 18F-FDOPA. Radiological review with a multidisciplinary team was performed for each patient. Results: One-hundred twenty-nine total lesions were identified using any of the four scans. DOTA sensitivity was 69% (89/129; 95% CI 61% to 76%) with a mean standardized uptake value (SUV) of 33.9 ± 30.1, FDOPA sensitivity was 18% (23/129; 95% CI 12% to 25%) with mean SUV of 12.1 ± 15.16. DOTA identified an additional 50 lesions not seen on CT (of which MRI detected 8 lesions with an average size 0.95 cm ± 0.48; 3 pancreatic, 2 duodenal, 2 liver, and 1 lymph node) and identified 55 lesions not seen on MRI (of which CT identified 13 with a mean size of 1.1 cm ± 0.45; 1 lung, 4 pancreatic, 2 duodenal, 1 liver, and 5 lymph nodes). Overall, CT detected 51.2% (66/129) of lesions (mean 0.61 cm ± 0.73; 95% CI 43% to 60%) and MRI detected 39.5% (51/129; 0.47 cm ± 0.71; 95% CI 32% to 48%), and there was no significant difference in the size of lesions detected (p=0.18). Analysis by organ NEN revealed equal sensitivity between FDOPA and DOTA for lung carcinoid, detecting 33% (4/12) of lesions, while CT detected 92% (11/12) of lesions. In the duodenum, DOTA identified 100% (11 /11) of lesions, while FDOPA had poor sensitivity (9%) in this location. Within the pancreas, DOTA has a sensitivity of 81% (31/38), while FDOPA had a sensitivity of 21% (8/38). CT localized 42% (16/38) of pancreatic lesions, of which MRI missed 6. Interestingly, DOTA missed 7 pancreatic lesions all approximately 1cm or larger, which is previously unrecognized (range 0.9 - 1.8cm). Twenty-three liver metastases were detected on anatomic imaging (CT identified 14, while MRI detected 15, with only 9 overlapping lesions). DOTA identified 60% (14/23) of lesions, of which 3 lesions were missed by CT and MRI. However, DOTA was more sensitive in the liver than FDOPA which only detected 2 lesions. FDOPA detected one lesion in the adrenal (0.9cm) that was not seen on DOTA. Conclusion: DOTA imaging proved to be superior to FDOPA, CT and MRI overall in detecting NENs in MEN1, specifically in the duodenum. Pancreatic NEN missed by DOTA may represent higher grade tumors and may benefit from 18FDG PET/CT imaging.

Background: Multiple Endocrine Neoplasia Type 1 (MEN1) is a rare inherited autosomal dominant disease predisposing patients to endocrine tumors. MEN1 can be genetically diagnosed at an early age. Patients are prone to develop benign parathyroid tumors then multifocal duodenopancreatic neuroendocrine tumors (dpNETs), which have a penetrance of >80% by age 80. Although they can be identified at an early stage, preventive measures do not exist, and one fifth of patients develop distant metastases, which is the most significant cause of mortality. Currently, no biomarkers can reliably predict which patients with MEN1-related dpNETs are at high risk of developing metastatic disease. Polyamines are naturally occurring polycationic alkylamines that have been implicated to play functional roles in promoting neoplastic transformation and growth. We have previously demonstrated a plasma polyamine signature that associates with pancreatic cancer development and that also offers value for predicting future distant metastasis in patients with triple-negative breast cancer. We hypothesized that such a plasma polyamine signature may similarly associate with disease progression in subjects with MEN1-related dpNET. Methods: As part of an international collaboration, we measured plasma polyamine levels using mass spectrometry from 14 MEN1 patients with distant metastatic dpNET (cases), 28 MEN1 patients with indolent dpNETs without distant metastases (control-1), and 14 MEN1 patients without dpNETs (control-2). Five circulating plasma polyamines were quantified in this initial test set. A combination rule was developed using logistic regression models. Findings were validated in an independent set of plasma from 6 cases and 22 controls (n=13 control-1 and n=9 control-2). Results: Area under the Receiver Operating Characteristic Curve (AUC) of individual polyamines delineating cases from controls ranged from 0.50-0.75 in the test set. A polyamine signature consisting of 3 polyamines developed in the test set yielded an AUC of 0.84 (95% CI: 0.63-1.00) with 67% sensitivity at 95% specificity in the validation set for distinguishing cases from controls. The predictive performance of the polyamine signature for distinguishing cases from MEN1 patients with indolent dpNETS without distant metastasis or MEN1 patients without dpNETS in the validation set was 0.79 (95% CI: 0.53-1.00) and 0.91 (95% CI: 0.75-1.00) with respective resultant sensitivity at 95% specificity of 50% and 67%. Conclusion: Our findings reveal a plasma polyamine signature associated with disease progression in subjects with MEN1-related dpNETs. This polyamine signature may provide a potential breakthrough for predicting progression and distant metastasis in MEN1 patients. Further prospective studies are warranted.