Multidisciplinary considerations for implementing Bayesian borrowing in basket trials.

Drug development has historically relied on phase I-III clinical trials including participants sharing the same disease. However, drug development has evolved as the discovery of mechanistic drivers of disease demonstrated that the same therapeutic target may provide benefits across different diseases. A basket trial condenses evaluation of one therapy among multiple related diseases into a single trial and presents an opportunity to borrow information across them rather than viewing each in isolation. Borrowing is a statistical tool but requires a foundation of clinical and therapeutic mechanistic justification. We review the Bayesian borrowing approach, including its assumptions, and provide a framework for how this approach can be evaluated for successful use in a basket trial for drug development.

The health care experience of adults with metabolic dysfunction-associated steatohepatitis and influence of PNPLA3: A qualitative study.

BACKGROUND: Metabolic dysfunction-associated steatohepatitis (MASH) is a progressive form of metabolic dysfunction-associated steatotic liver disease, for which there is limited information about patient experience, including the patient journey. METHODS: In this study, we conducted interviews with patients with MASH to qualitatively evaluate the patient journey and help elucidate the experiences of this patient population. We also investigated if the patatin-like phospholipase domain-containing protein 3 (PNPLA3) I148M variant (non-Hispanic) or being of Hispanic ethnicity may influence patient experiences because these 2 subgroups develop advanced liver disease more frequently than other patient groups. RESULTS: One-to-one interviews were conducted with 28 adults (with PNPLA3 I148M genetic variant, n = 10; Hispanic, n = 8) living in the United States who had been diagnosed with MASH with liver fibrosis. Patients were asked open-ended questions about their experiences before, at, and after their diagnosis. The data collected found that patients experienced a long process of misdiagnoses before their diagnosis of MASH, a lack of clear information provided by clinicians, and limited accessibility to support groups. Hispanic patients reported "impact on family/friends" (75%) and "fear of disease progression" (75%) more frequently than the other patient cohorts interviewed. This is the first report of "fear of progression" in patients with MASH. No patients who were White and had the PNPLA3 I148M variant reported nausea/vomiting, in contrast to other patient cohorts. CONCLUSIONS: This qualitative study identified key aspects of the patient journey that are important for clinical providers and medical teams to recognize. We also propose a new algorithm that could be developed to help screen relatives of patients who are found to carry the PNPLA3 I148M variant.

Non-invasive assessment of hepatic steatosis by ultrasound-derived fat fraction in individuals at high-risk for metabolic dysfunction-associated steatotic liver disease.

AIMS: Given the increasing number of individuals developing metabolic dysfunction-associated steatotic liver disease (MASLD) and the low rate of those with progressive liver disease, there is a pressing need to conceive affordable biomarkers to assess MASLD in general population settings. Herein, we aimed to investigate the performance of the ultrasound-derived fat fraction (UDFF) for hepatic steatosis in high-risk individuals. METHODS: A total of 302 Europeans with obesity, type 2 diabetes, or a clinical history of hepatic steatosis were included in the analyses. Clinical, laboratory, and imaging data were collected using standardized procedures during a single screening visit in Rome, Italy. Hepatic steatosis was defined by controlled attenuation parameter (CAP) or ultrasound-based Hamaguchi's score. UDFF performance for hepatic steatosis was estimated by the area under the receiver operating characteristic curve (AUC). RESULTS: Overall, median (IQR) UDFF was 12% (7-20). UDFF was positively correlated with CAP (ρ = 0.73, p < 0.0001) and Hamaguchi's score (ρ = 0.79, p < 0.0001). Independent predictors of UDFF were circulating triglycerides, alanine aminotransferase (ALT), and ultrasound-measured visceral adipose tissue (VAT). UDFF AUC was 0.89 (0.85-0.93) and 0.92 (0.88-0.95) for CAP- and ultrasound-diagnosed hepatic steatosis, respectively. UDFF AUC for hepatic steatosis was higher than those of fatty liver index (FLI), hepatic steatosis index (HSI), CAP-score (CAPS), and ALT (p < 0.0001). Lower age, ALT, and VAT were associated with discordance between UDFF and ultrasound. CONCLUSIONS: UDFF may be a simple and accurate imaging biomarker to assess hepatic steatosis and monitor changes in hepatic fat content over time or in response to therapeutic interventions beyond clinical trials.

The greater impact of PNPLA3 polymorphism on liver-related events in Japanese non-alcoholic fatty liver disease patients: A multicentre cohort study.

BACKGROUND & AIMS: PNPLA3 rs738409 has been associated with an increased risk of liver-related events in patients with non-alcoholic fatty liver disease (NAFLD). In this study, we investigated the epidemiology of NAFLD and the impact of PNPLA3 on prognosis in Japan. METHODS: A longitudinal multicentre cohort study, the JAGUAR study, includes 1550 patients with biopsy-proven NAFLD in Japan. We performed genetic testing and evaluated outcomes from this cohort. Liver-related events were defined as hepatocellular carcinoma (HCC) and decompensated liver cirrhosis events. RESULTS: During follow-up (median [range], 7.1 [1.0-24.0] years), 80 patients developed HCC, 104 developed liver-related events, and 59 died of any cause. The 5-year rate of liver-related events for each single-nucleotide polymorphism was 0.5% for CC, 3.8% for CG, and 5.8% for GG. Liver-related deaths were the most common (n = 28); only three deaths were due to cardiovascular disease. Multivariate analysis identified carriage of PNPLA3 CG/GG (hazard ratio [HR] 16.04, p = .006) and FIB-4 index >2.67 (HR 10.70, p < .01) as predictors of liver-related event development. No HCC or liver-related death was found among patients with PNPLA3 CC. There was a significantly increased risk of HCC, liver-related events, and mortality for CG/GG versus CC, but no difference between the CG and GG genotypes. CONCLUSIONS: In Japanese individuals, the main cause of death from NAFLD is liver-related death. The greater risk of liver-related events incurred by PNPLA3 G allele was shown in Japan. Risk stratification for NAFLD in Japan is best accomplished by integrating PNPLA3 with the FIB-4 index.

Blood-based Proteomic Signatures Associated With MEN1-related Duodenopancreatic Neuroendocrine Tumor Progression.

PURPOSE: Patients with multiple endocrine neoplasia type 1 (MEN1) are predisposed to develop duodenopancreatic neuroendocrine tumors (dpNETs), and metastatic dpNET is the primary cause of disease-related mortality. Presently, there is a paucity of prognostic factors that can reliably identify patients with MEN1-related dpNETS who are at high risk of distant metastasis. In the current study, we aimed to establish novel circulating molecular protein signatures associated with disease progression. EXPERIMENTAL DESIGN: Mass spectrometry-based proteomic profiling was conducted on plasmas procured through an international collaboration between MD Anderson Cancer Center, the National Institutes of Health, and the University Medical Center Utrecht from a cohort of 56 patients with MEN1 [14 with distant metastasis dpNETs (cases) and 42 with either indolent dpNETs or no dpNETs (controls)]. Findings were compared to proteomic profiles generated from serially collected plasmas from a mouse model of Men1-pancreatic neuroendocrine tumors (Men1fl/flPdx1-CreTg) and control mice (Men1fl/fl). RESULTS: A total of 187 proteins were found to be elevated in MEN1 patients with distant metastasis compared to controls, including 9 proteins previously associated with pancreatic cancer and other neuronal proteins. Analyses of mouse plasmas revealed 196 proteins enriched for transcriptional targets of oncogenic MYCN, YAP1, POU5F1, and SMAD that were associated with disease progression in Men1fl/flPdx1-CreTg mice. Cross-species intersection revealed 19 proteins positively associated with disease progression in both human patients and in Men1fl/flPdx1-CreTg mice. CONCLUSIONS: Our integrated analyses identified novel circulating protein markers associated with disease progression in MEN1-related dpNET.

Determination of FGF23 Levels for the Diagnosis of FGF23-Mediated Hypophosphatemia.

Fibroblast growth factor-23 (FGF23) measurement is a critical tool in the evaluation of patients with disordered phosphate homeostasis. Available laboratory reference ranges for blood FGF23 were developed using samples from normophosphatemic individuals. Reliance on such values can lead to misdiagnosis in patients with FGF23-mediated hypophosphatemia, such as X-linked hypophosphatemia (XLH) and tumor-induced osteomalacia (TIO), in whom pathology-driving FGF23 levels can be in the "normal range." To determine FGF23 levels that are diagnostic for the identification of patients with FGF23-mediated hypophosphatemic disorders, we studied 149 patients with various disorders of FGF23-mediated and FGF23-independent hypophosphatemia and defined cut-off levels for both intact FGF23 (iFGF23) and C-terminal FGF23 (cFGF23) that can accurately distinguish between FGF23-mediated and FGF23-independent hypophosphatemia. In addition, to demonstrate the relationship between FGF23 and phosphate across the spectrum of human physiology, we assessed blood levels of FGF23 and phosphate in 434 patients with various forms of hypophosphatemia, hyperphosphatemia, and normophosphatemia. An intact FGF23 cut point of 27 pg/mL was 100% sensitive and specific in distinguishing FGF23-mediated from FGF23-independent hypophosphatemia, and a cFGF23 cut point of 90 RU/mL was 100% sensitive and specific in distinguishing specifically TIO from FGF23-independent hypophosphatemia. There was overlap in the cFGF23 range of 45-90 RU/mL between genetic forms of FGF23 excess and FGF23-independent hypophosphatemia, substantiating the superiority of iFGF23 over cFGF23 in making the diagnosis of FGF23-mediated hypophosphatemia. In this cohort, using the laboratory upper limit of normal for cFGF23 (180 RU/mL) would result in a misdiagnosis in more than half of patients with FGF23-mediated hypophosphatemia. In this, the largest study of FGF23 in chronic hypophosphatemia to date, we established iFGF23 and cFGF23 cut-off values to assist in the evaluation and diagnosis of hypophosphatemic conditions. © 2022 American Society for Bone and Mineral Research (ASBMR). This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Metastatic Grade 3 Neuroendocrine Tumor in Multiple Endocrine Neoplasia Type 1 Expressing Somatostatin Receptors.

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.

Parathyroid Hormone Resistance and Autoantibodies to the PTH1 Receptor.

We describe two cases of acquired parathyroid hormone (PTH) resistance consequent to the development of serum PTH type 1 receptor (PTH1R) autoantibodies, which block PTH binding and signaling. Both cases were associated with other autoimmune manifestations, and one case was associated with atypical membranous glomerulonephritis. In vitro binding and signaling assays identified the presence of PTH1R-blocking IgG autoantibodies, which were not present in serum samples from patients with other renal or autoimmune disorders. (Funded by the Intramural Research Programs of the National Institute of Diabetes and Digestive and Kidney Diseases and others.).

Two distinct classes of thymic tumors in patients with MEN1 show LOH at the MEN1 locus.

Patients with the multiple endocrine neoplasia type 1 (MEN1) syndrome carry germline heterozygous loss-of-function mutations in the MEN1 gene which predisposes them to develop various endocrine and non-endocrine tumors. Over 90% of the tumors show loss of heterozygosity (LOH) at chromosome 11q13, the MEN1 locus, due to somatic loss of the wild-type MEN1 allele. Thymic neuroendocrine tumors (NETs) or thymic carcinoids are uncommon in MEN1 patients but are a major cause of mortality. LOH at the MEN1 locus has not been demonstrated in thymic tumors. The goal of this study was to investigate the molecular aspects of MEN1-associated thymic tumors including LOH at the MEN1 locus and RNA-sequencing (RNA-Seq) to identify genes associated with tumor development and potential targeted therapy. A retrospective chart review of 294 patients with MEN1 germline mutations identified 14 patients (4.8%) with thymic tumors (12 thymic NETs and 2 thymomas). LOH at the MEN1 locus was identified in 10 tumors including the 2 thymomas, demonstrating that somatic LOH at the MEN1 locus is also the mechanism for thymic tumor development. Unsupervised principal component analysis and hierarchical clustering of RNA-Seq data showed that thymic NETs formed a homogenous transcriptomic group separate from thymoma and normal thymus. KSR2 (kinase suppressor of Ras 2), that promotes Ras-mediated signaling, was abundantly expressed in thymic NETs, a potential therapeutic target. The molecular insights gained from our study about thymic tumors combined with similar data from other MEN1-associated tumors may lead to better surveillance and treatment of these rare tumors.

Validity of Secretin Stimulation Testing on Proton Pump Inhibitor Therapy for Diagnosis of Zollinger-Ellison Syndrome.

INTRODUCTION: Zollinger-Ellison syndrome (ZES) is characterized by gastrinoma-induced hypergastrinemia causing excessive gastric acid secretion. Secretin stimulation tests (SSTs) are required for diagnosis in the majority of patients. Two case reports suggest that proton pump inhibitors (PPIs) cause false SST results. Consequently, PPIs are discontinued to allow hyperchlorhydria to recur; however, uncontrolled acidity can cause life-threatening complications in those with underlying undiagnosed ZES. The aim of this study was to determine whether PPIs influence the validity of SSTs for the diagnosis of ZES. METHODS: A retrospective chart review was performed. Charts of patients who underwent SSTs were reviewed to determine whether they were performed on or off PPI and the test's accuracy by comparing the results with gold standard tests (diagnostic laboratory testing performed off PPI or surgical pathology consistent with gastrinoma). Sensitivity, specificity, and positive predictive value (PPV) of SST on PPI were calculated and results compared with SST off PPI using noninferiority analyses. RESULTS: Twenty-eight patients corresponding to 29 SSTs were performed on PPI, and 70 patients corresponding to 107 SSTs were performed off PPI. Most of them were female and white and had multiple endocrine neoplasia type 1. We found no false-positive or false-negative SSTs on PPI. Sensitivity, specificity, and PPV of SSTs on PPI were determined to be noninferior to SSTs off PPI (P ≤ 0.05 for all). DISCUSSION: In our cohort, SSTs on PPI compared with SSTs off PPI were noninferior for sensitivity, specificity, and PPV. These results suggest that PPI withdrawal before SSTs may not be necessary.

A Blood-based Polyamine Signature Associated With MEN1 Duodenopancreatic Neuroendocrine Tumor Progression.

CONTEXT: Duodenopancreatic neuroendocrine tumors (dpNETs) frequently occur in patients with multiple endocrine neoplasia type 1 (MEN1), and metastatic dpNET is the primary cause of disease-related mortality. There is a need for biomarkers that can identify patients with MEN1-related dpNETs that are at high risk of developing distant metastasis. Polyamines have tumor-promoting roles in several cancer types. OBJECTIVE: We hypothesized that MEN1-dpNET-related disease progression is associated with elevated levels of circulating polyamines. METHODS: Through an international collaboration between The University of Texas MD Anderson Cancer Center, the National Institutes of Health, and the University Medical Center Utrecht, plasma polyamine levels were assessed using mass spectrometry in 84 patients with MEN1 (20 with distant metastatic dpNETs [patients] and 64 with either indolent dpNETs or no dpNETs [controls]). A mouse model of MEN1-pNET, Men1fl/flPdx1-CreTg, was used to test time-dependent changes in plasma polyamines associated with disease progression. RESULTS: A 3-marker plasma polyamine signature (3MP: N-acetylputrescine, acetylspermidine, and diacetylspermidine) distinguished patients with metastatic dpNETs from controls in an initial set of plasmas from the 3 participating centers. The fixed 3MP yielded an area under the curve of 0.84 (95% CI, 0.62-1.00) with 66.7% sensitivity at 95% specificity for distinguishing patients from controls in an independent test set from MDACC. In Men1fl/flPdx1-CreTg mice, the 3MP was elevated early and remained high during disease progression. CONCLUSION: Our findings provide a basis for prospective testing of blood-based polyamines as a potential means for monitoring patients with MEN1 for harboring or developing aggressive disease.

Cockayne syndrome, MEN1, and genomic variants: Exome sequencing is changing our view of the genetic landscape.

The availability of genomic sequencing for inherited diseases provides a more complete molecular basis for how an individual's genetic landscape influences clinical outcome. We describe a family where exome sequencing of a 3-year-old boy with clinical features of Cockayne syndrome (CS) confirmed the diagnosis of CS. He also had a mutation consistent with a pre-symptomatic second disease, multiple endocrine neoplasia type 1 (MEN1), each potentially affecting multiple organ systems, in addition to a poorly defined variant in fumarate hydratase (FH). Genomic sequencing may reveal coexisting pathogenic mutations and variants which complicate clinical interpretation.

Familial Hyperparathyroidism.

Regulation of the serum calcium level in humans is achieved by the endocrine action of parathyroid glands working in concert with vitamin D and a set of critical target cells and tissues including osteoblasts, osteoclasts, the renal tubules, and the small intestine. The parathyroid glands, small highly vascularized endocrine organs located behind the thyroid gland, secrete parathyroid hormone (PTH) into the systemic circulation as is needed to keep the serum free calcium concentration within a tight physiologic range. Primary hyperparathyroidism (HPT), a disorder of mineral metabolism usually associated with abnormally elevated serum calcium, results from the uncontrolled release of PTH from one or several abnormal parathyroid glands. Although in the vast majority of cases HPT is a sporadic disease, it can also present as a manifestation of a familial syndrome. Many benign and malignant sporadic parathyroid neoplasms are caused by loss-of-function mutations in tumor suppressor genes that were initially identified by the study of genomic DNA from patients who developed HPT as a manifestation of an inherited syndrome. Somatic and inherited mutations in certain proto-oncogenes can also result in the development of parathyroid tumors. The clinical and genetic investigation of familial HPT in kindreds found to lack germline variants in the already known HPT-predisposition genes represents a promising future direction for the discovery of novel genes relevant to parathyroid tumor development.

Acute oesophageal necrosis in multiple endocrine neoplasia type 1: an undescribed complication.

Acute oesophageal necrosis (AEN) is a rare entity that most commonly presents as upper gastrointestinal bleeding. Complex pathophysiology may include oesophageal ischaemia as well as reflux of acidic gastric contents causing oesophageal mucosal injury. Management is supportive and directed at underlying comorbidities however prognosis is poor with complications such as oesophageal perforation, stricture and stenosis. Here we present the case of a 56-year-old man with multiple endocrine neoplasia type 1 (MEN1) and gastro-oesophageal reflux disease who developed AEN as a result of undiagnosed Zollinger-Ellison syndrome (ZES), duodenal ulcer-induced obstruction and hypotension from new-onset atrial fibrillation. AEN as the presentation of MEN1-associated ZES is an unusual presentation of this disease which clinicians, particularly endocrinologists and endoscopists, should be aware of.

Insulin sensitivity and pancreatic ß-cell function in patients with primary aldosteronism.

BACKGROUND: Primary aldosteronism (PA) is associated with an increased risk for dysglycemia. However, the effects of hyperaldosteronism on insulin sensitivity and ß-cell function are unclear. METHODS: Using a cross-sectional study design, we assessed insulin sensitivity and pancreatic ß-cell function from an oral glucose tolerance test (OGTT) in patients from two cohorts: subjects with PA (n = 21) and essential hypertension control (EHC) subjects (n = 22). Age, sex, BMI, and mean arterial pressure adjusted measures of insulin sensitivity and ß-cell function were compared between the groups. RESULTS: PA individuals were less insulin sensitive compared to EHC subjects (Quantitative insulin sensitivity check index [QUICKI]: 0.340 ± 0.006 vs. 0.374 ± 0.013, p < 0.001; Matsuda index: 4.14 ± 0.49 vs. 7.87 ± 1.42, p < 0.001; SI: 11.45 ± 4.85 vs. 21.23 ± 6.11 dL/kg/min per µU/mL, p = 0.02). The hepatic insulin resistance index (HIRI) was higher in PA subjects (PA: 5.61 ± 1.01 vs. EHC: 4.13 ± 0.61, p = 0.002). The insulinogenic index (IGI), an index of ß-cell function was higher in the PA cohort (PA: 1.49 ± 0.27 vs. 1.11 ± 0.21 µU/mL/mg/dL, p = 0.03). However, the oral disposition index (DI) was similar between the groups (PA: 4.77 ± 0.73 vs. EHC: 5.46 ± 0.85, p = 0.42), which likely accounts for the similar glucose tolerance between the two cohorts, despite lower sensitivity. CONCLUSIONS: In summary, insulin sensitivity is significantly lower in PA with an appropriately compensated ß-cell function. These results suggest that excess aldosterone and/or other steroids in the context of PA may negatively affect insulin action without adversely impacting ß-cell function.

Patients With MEN1 Are at an Increased Risk for Venous Thromboembolism.

BACKGROUND: Multiple endocrine neoplasia type 1 (MEN1) is a rare inherited disorder predisposing the development of multiple functional and nonfunctional neuroendocrine tumors (NETs). Only uncommon MEN1-associated functional NETs such as glucagonomas (<1%) and adenocorticotropic hormone-producing tumors (<5%) are known to be associated with hypercoagulability. It is unknown if patients with MEN1 generally have an increased risk of venous thromboembolism (VTE). METHODS: We queried a prospective natural history study of germline mutation-positive MEN1 patients (n = 286) between 1991 and 2019 for all lifetime events of VTE. The search terms were: DVT, thromb, embol, PE, pulmonary embolism, clot, hematology consult, anticoagulant, coumadin, lovenox, xarelto, warfarin, aspirin, rivaroxaban, and apixaban. Incidence rates were calculated, accounting for age and sex. Comparisons were made to published incidence rates in healthy populations, different types of cancer, and Cushing's syndrome. RESULTS: Thirty-six subjects (median age 45 years, range 16-75) experienced a VTE event, yielding a prevalence rate of 12.9%. The age-sex adjusted incidence rate of VTE is 9.11 per 1000 patient-years, with a sex-adjusted lifetime incidence rate of 2.81 per 1000 patient-years. MEN1-associated lifetime incidence rates are ~2-fold higher than the estimated annual incidence rate in the general population and are comparable to the known risk in the setting of various types of cancer. Approximately 80% of patients who had a VTE were diagnosed with pancreatic NETs, of which 24% were insulinomas. Fourteen patients (42%) experienced perioperative VTE events. CONCLUSIONS: MEN1 patients have an increased risk of VTE. Further mechanistic investigation and validation from other MEN1 cohorts are needed to confirm the increased prevalence of VTE in MEN1.

Distinct DNA Methylation Signatures in Neuroendocrine Tumors Specific for Primary Site and Inherited Predisposition.

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.

c-MET inhibition: novel treatment for sporadic and MEN1-associated GEP NETs.

Gastroenteropancreatic neuroendocrine tumors (GEP NETs) comprise a heterogenous and diverse group of neoplasms arising from a common neuroendocrine cell origin. The majority of these tumors occur sporadically while ~20% manifest within the context of hereditary syndromes. Germline MEN1 mutations cause a syndrome with an increased susceptibility to multifocal primary GEP NETs. In addition, somatic MEN1 mutations also occur in these sporadic lesions. MEN1 alterations are the most frequent somatic mutation found in pancreatic neuroendocrine tumors. In this review, we explore the implication of the loss of the MEN1-encoded protein menin as a key pathogenic driver in subsets of GEP NETs with downstream consequences including upregulation of the oncogenic receptor c-MET (hepatocyte growth factor receptor). Furthermore, the review will summarize the data related to the clinical presentation, therapeutic standards, and outcomes of these tumors in both sporadic and germline MEN1 mutation-associated contexts. Finally, we present the data on c-MET expression in GEP NETs, clinical trials using c-MET inhibitors and provide an overview of the molecular mechanisms by which c-MET inhibition in these lesions represents a potential precision-medicine targeted approach.

18F-FDOPA PET/CT accurately identifies MEN1-associated pheochromocytoma.

SUMMARY: Pheochromocytoma (PHEO) in multiple endocrine neoplasia type 1 (MEN1) is extremely rare. The incidence is reported as less than 2%. We report a case of a 76-year-old male with familial MEN1 who was found to have unilateral PHEO. Although the patient was normotensive and asymptomatic, routine screening imaging with CT demonstrated bilateral adrenal masses. The left adrenal mass grew from 2.5 to 3.9 cm over 4 years with attenuation values of 9 Hounsfield units (HU) pre-contrast and 15 HU post-contrast washout. Laboratory evaluation demonstrated an adrenergic biochemical phenotype. Both 18F-fluorodeoxyglucose (18F-FDG) PET/CT and 123I-metaiodobenzylguanidine (123I-mIBG) scintigraphy demonstrated bilateral adrenal uptake. In contrast, 18F-fluorodihydroxyphenylalanine (18F-FDOPA) PET/CT demonstrated unilateral left adrenal uptake (28.7 standardized uptake value (SUV)) and physiologic right adrenal uptake. The patient underwent an uneventful left adrenalectomy with pathology consistent for PHEO. Post-operatively, he had biochemical normalization. A review of the literature suggests that adrenal tumors >2 cm may be at higher risk for pheochromocytoma in patients with MEN1. Despite a lack of symptoms related to catecholamine excess, enlarging adrenal nodules should be biochemically screened for PHEO. 18F-FDOPA PET/CT may be beneficial for localization in these patients. LEARNING POINTS: 18F-FDOPA PET/CT is a beneficial imaging modality for identifying pheochromocytoma in MEN1 patients. Adrenal adenomas should undergo routine biochemical workup for PHEO in MEN1 and can have serious peri-operative complications if not recognized, given that MEN1 patients undergo frequent surgical interventions. MEN1 is implicated in the tumorigenesis of PHEO in this patient.