Multiple endocrine neoplasia type 1 (MEN1): Not only inherited endocrine tumors

Mirrored Metastatic Neuroendocrine Tumor in a Mother-Daughter Duo With Mutations in the MEN1 Gene

Multiple endocrine neoplasia (MEN) 1 syndrome may present with either of any or all neuroendocrine tumors (NETs), parathyroid and pituitary adenoma. There is a paucity of data on the intronic and exonic mutations in the MEN1 gene associated with the MEN1 syndrome. We present an interesting study of a mother-daughter duo of MEN1 who had a similar lesions distribution of metastatic NET and underwent genetic analysis to reveal a rare mutation in the MEN1 gene and both first-degree relatives presented with metastatic NET without any other syndromic manifestation of MEN1 syndrome. Both patients received peptide receptor radionuclide therapy.

A comprehensive high-throughput screening approach for discovering inhibitors targeting the menin-MLL1 interaction

The prognosis for mixed-lineage leukemia (MLL), particularly in young children, remains a significant health concern due to the limited therapeutic options available. MLL refers to KMT2A chromosomal translocations that produce MLL fusion proteins. The protein menin, which is essential for the malignant potential of these MLL fusion proteins, offers novel targets for acute leukemia treatment. This study reports the identification of potential new inhibitors of MLL-mediated leukemia targeting menin through the screening of two distinct drug libraries and existing inhibitors. The 3D structure of the protein was retrieved from the Protein Data Bank (ID: 8IG0). The drug libraries, sourced from public repositories such as the 'Epigenetic Drug Library' and 'The FDA-anticancer Drug Library,' yielded top candidates like Tozaseritib and Panobinostat, which exhibited the highest binding energy scores in the Glide virtual screening module. Additionally, 31 known menin-MLL1 inhibitors were identified through PDB screening and subsequently docked with the menin protein. The top three inhibitors (M-525, M-808, and MI-89) were selected for further analysis. Five menin-ligand complexes were validated using molecular dynamics analysis and Molecular Mechanics Poisson-Boltzmann Surface Area (MM-PBSA) calculations to verify the stability and binding mechanisms.These findings provide insights into the molecular mechanisms of these drugs and lay the groundwork for future clinical development aimed at improving outcomes for acute myeloid leukemia (AML) patients.

A novel likely pathogenetic variant p.(Cys235Arg) of the MEN1 gene in multiple endocrine neoplasia type 1 with multifocal glucagonomas

PURPOSE

Multiple endocrine neoplasia type 1 (MEN1) is a hereditary endocrine syndrome caused by pathogenic variants in MEN1 tumor suppressor gene. Diagnosis is commonly based on clinical criteria and confirmed by genetic testing. The objective of the present study was to report on a MEN1 case characterized by multiple pancreatic glucagonomas, with particular concern on the possible predisposing genetic defects.

METHODS

While conducting an extensive review of the most recent scientific evidence on the unusual glucagonoma familial forms, we analyzed the MEN1 gene in a 35-year-old female with MEN1, as well as her son and daughter, using Sanger and next-generation sequencing (NGS) approaches. We additionally explored the functional and structural consequences of the identified variant using in silico analyses.

RESULTS

NGS did not show any known pathogenic variant in the tested regions. However, a new non-conservative variant in exon 4 of MEN1 gene was found in heterozygosity in the patient and in her daughter, resulting in an amino acid substitution from hydrophobic cysteine to hydrophilic arginine at c.703T > C, p.(Cys235Arg). This variant is absent from populations databases and was never reported in full papers: its characteristics, together with the high specificity of the patient's clinical phenotype, pointed toward a possible causative role.

CONCLUSION

Our findings confirm the need for careful genetic analysis of patients with MEN1 and establish a likely pathogenic role for the new p.(Cys235Arg) variant, at least in the rare subset of MEN1 associated with glucagonomas.

Persistent hypercalcaemia associated with two pathogenic variants in the CYP24A1 gene and a parathyroid adenoma-a case report and review

Introduction

24-Hydroxylase, encoded by the CYP24A1 gene, is a crucial enzyme involved in the catabolism of vitamin D. Loss-of-function mutations in CYP24A1 result in PTH-independent hypercalcaemia with high levels of 1,25(OH)2D3. The variety of clinical manifestations depends on age, and underlying genetic predisposition mutations can lead to fatal infantile hypercalcaemia among neonates, whereas adult symptoms are usually mild.

Aim of the study

We report a rare case of an adult with primary hyperparathyroidism and loss-of-function mutations in the CYP24A1 gene and a review of similar cases.

Case presentation

We report the case of a 58-year-old woman diagnosed initially with primary hyperparathyroidism. Preoperatively, the suspected mass adjoining the upper pole of the left lobe of the thyroid gland was found via ultrasonography and confirmed by 99mTc scintigraphy and biopsy as the parathyroid gland. The patient underwent parathyroidectomy (a histopathology report revealed parathyroid adenoma), which led to normocalcaemia. After 10 months, vitamin D supplementation was introduced due to deficiency, and the calcium level remained within the reference range. Two years later, biochemical tests showed recurrence of hypercalcaemia with suppressed parathyroid hormone levels and elevated 1,25(OH)2D3 concentrations. Further investigation excluded the most common causes of PTH-independent hypercalcaemia, such as granulomatous disease, malignancy, and vitamin D intoxication. Subsequently, vitamin D metabolites were measured using LC-MS/MS, which revealed high levels of 25(OH)D3, low levels of 24,25(OH)2D3 and elevated 25(OH)2D3/24,25(OH)2D3 ratios, suggesting a defect in vitamin D catabolism. Molecular analysis of the CYP24A1 gene using the NGS technique revealed two pathogenic variants: p.(Arg396Trp) and p.(Glu143del) (rs114368325 and rs777676129, respectively).

Conclusions

The diagnostic process for hypercalcaemia becomes complicated when multiple causes of hypercalcaemia coexist. The measurement of vitamin D metabolites using LC-MS/MS may help to identify carriers of CYP24A1 mutations. Subsequent molecular testing may contribute to establishing the exact frequency of pathogenic variants of the CYP24A1 gene and introducing personalized treatment.

PDP type brain tumor in association with multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant syndrome caused by inactivating pathogenic variants in the tumor suppressor gene menin 1 on chromosome 11q13 (Falchetti et al., 2009). The syndrome is characterized by neoplasia in two or more endocrine glands and has a high degree of penetrance. Pathogenic germline multiple neoplasia type 1 variants primarily result in neoplasia affecting the parathyroid glands, the pancreatic islet cells, and the anterior pituitary in combination. Primary hyperparathyroidism is the most common pathological manifestation of the syndrome, followed by pancreatic neuroendocrine tumors. Important genetic confirmation has been provided showing that ependymoma should be considered as a neoplasm that can occur in patients with MEN1 (Kato et al., 1996; Cuevas-Ocampo et al., 2017). The biphasic histopathological tumor entity shown in the present case we name Pleomorphic Xanthoastocytoma grade 3 differential pathology (PDP) in association with Multiple Endocrine Neoplasia type 1. This MEN1 associated tumor subtype is an extension of the findings on MEN1 associated ependymoma, where we show that the clinical phenotype itself may potentially be triggered by a frameshift germline pathogenic variant for the MEN1 gene, in combination with cyclin-dependent kinase inhibitor 1B gene germline variant and cyclin dependent kinase inhibitor 2A somatic deletion downstream of menin.

Multifocal Insulinoma as the Unique Presenting Feature of Multiple Endocrine Neoplasia Type 1 in an Adolescent

INTRODUCTION

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant inherited disorder defined by the presence of two of the following endocrinopathies: primary hyperparathyroidism, anterior pituitary tumors, and duodenopancreatic neuroendocrine tumors (NETs). NETs, which can secrete hormones including insulin, gastrin, and glucagon, among others, are common in patients with MEN1 and are a major cause of morbidity and premature death. NETs are more common later in life, with very few cases described in children. Here, we describe a unique case of an adolescent with multifocal pancreatic NETs as the single presenting feature of MEN1.

CASE PRESENTATION

A 13-year-old healthy male presented with severe weakness, altered mental status, and syncope in the setting of a venous blood glucose (BG) of 36 mg/dL. Workup showed an elevated insulin level (14 μIU/mL) when BG was 39 mg/dL with positive response to glucagon, concerning for hyperinsulinism. Diazoxide and chlorothiazide were started but not well tolerated secondary to emesis. Three suspected NETs were identified by magnetic resonance imaging and 68-Ga DOTATATE PET-CT imaging, including the largest, a 2.1 cm mass in the pancreatic head. A fourth mass in the pancreatic tail was identified via intraoperative ultrasound. All lesions were successfully enucleated and excised, and glucose levels normalized off diazoxide by post-op day 2. While the primary lesion stained for insulin and somatostatin by immunofluorescence (IF), consistent with his clinical presentation, the additional tumors expressed glucagon, somatostatin, pancreatic polypeptide, and chromogranin A but were negative for insulin. Genetic testing confirmed a pathogenic heterozygous mutation in MEN1 (c.969C>A, p.Tyr323). He had no other signs of MEN-associated comorbidities on screening.

DISCUSSION/CONCLUSION

This case demonstrates that young patients with MEN1 can present with multifocal NETs. These NETs may have polyhormonal expression patterns despite a clinical presentation consistent with one primary hormone. Our patient had clinical symptoms and laboratory evaluation consistent with an insulinoma but was found to have four NETs, each with different IF staining patterns. Advanced preoperative and intraoperative imaging is important to identify and treat all present NETs. Moreover, serum hormone levels pre- and posttreatment could help evaluate whether NETs are actively secreting hormones into the bloodstream or simply expressing them within the pancreas. Finally, this case highlights the importance of genetic testing for MEN1 in all young patients with insulinomas.

INTRODUCTION

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant inherited disorder defined by the presence of two of the following endocrinopathies: primary hyperparathyroidism, anterior pituitary tumors, and duodenopancreatic neuroendocrine tumors (NETs). NETs, which can secrete hormones including insulin, gastrin, and glucagon, among others, are common in patients with MEN1 and are a major cause of morbidity and premature death. NETs are more common later in life, with very few cases described in children. Here, we describe a unique case of an adolescent with multifocal pancreatic NETs as the single presenting feature of MEN1.

CASE PRESENTATION

A 13-year-old healthy male presented with severe weakness, altered mental status, and syncope in the setting of a venous blood glucose (BG) of 36 mg/dL. Workup showed an elevated insulin level (14 μIU/mL) when BG was 39 mg/dL with positive response to glucagon, concerning for hyperinsulinism. Diazoxide and chlorothiazide were started but not well tolerated secondary to emesis. Three suspected NETs were identified by magnetic resonance imaging and 68-Ga DOTATATE PET-CT imaging, including the largest, a 2.1 cm mass in the pancreatic head. A fourth mass in the pancreatic tail was identified via intraoperative ultrasound. All lesions were successfully enucleated and excised, and glucose levels normalized off diazoxide by post-op day 2. While the primary lesion stained for insulin and somatostatin by immunofluorescence (IF), consistent with his clinical presentation, the additional tumors expressed glucagon, somatostatin, pancreatic polypeptide, and chromogranin A but were negative for insulin. Genetic testing confirmed a pathogenic heterozygous mutation in MEN1 (c.969C>A, p.Tyr323). He had no other signs of MEN-associated comorbidities on screening.

DISCUSSION/CONCLUSION

This case demonstrates that young patients with MEN1 can present with multifocal NETs. These NETs may have polyhormonal expression patterns despite a clinical presentation consistent with one primary hormone. Our patient had clinical symptoms and laboratory evaluation consistent with an insulinoma but was found to have four NETs, each with different IF staining patterns. Advanced preoperative and intraoperative imaging is important to identify and treat all present NETs. Moreover, serum hormone levels pre- and posttreatment could help evaluate whether NETs are actively secreting hormones into the bloodstream or simply expressing them within the pancreas. Finally, this case highlights the importance of genetic testing for MEN1 in all young patients with insulinomas.

Answering Big Questions in Pain Medicine

The future of pain medicine is marked by many questions. What can other nations around the world learn from the opioid crisis that is still affecting the United States? The American opioid experience was mischaracterized and wrongly described, and its causes were misdiagnosed from the outset, leading to its mismanagement and the abandonment of many chronic pain patients to their suffering. There are a few new drugs in the analgesic armamentarium. What new targets do we have in pain medicine? There are many breakthroughs, discoveries, and potential new targets that could add to our analgesic prescribing choices. These include sigma receptors, d-amino acid oxidase, endoplasmic reticulum stress receptors, histone deacetylase, and others. Neuromodulation had been used with varying degrees of success for years, but with a simplistic approach based on the gate theory of pain. Despite our familiarity with neuromodulation and spinal cord stimulators, neuromodulation research indicates that the activation of glial cells may activate the immune system and enhance analgesia. Neuromodulation studies have concentrated on how electricity affects neuronal activity rather than how electrical activity could reduce pain. There are still more frontiers in our battle against pain and some promising avenues for treatments. This narrative review will try to summarize what can be done from the perspective of recent technological and pharmacological developments.

Mediastinal Intrathymic Parathyroid Adenoma: A Case Report and Review of the Literature

The classic clinical vignette of primary hyperparathyroidism is well described as "bones, stones, abdominal moans, and psychiatric overtones" to reflect the effects of excess parathyroid hormone (PTH) and calcium. Most commonly, primary hyperparathyroidism is due to a functional parathyroid adenoma situated by the thyroid gland. Rarely, the primary focus of autonomously produced PTH is located ectopically within the mediastinum. A 19-year-old Caucasian female with no relevant past medical history presented to the emergency department with tachycardia, nausea, vomiting, and a five-day history of vague, mid-abdominal pain. Initial computed tomography (CT) with contrast of the abdomen and pelvis was negative for acute findings, and she subsequently underwent biochemical screening. The patient was found to have elevated serum calcium and PTH, raising suspicion for the diagnosis of primary hyperparathyroidism. Further evaluation for a parathyroid adenoma was negative by a CT scan of the neck and thyroid ultrasound. A nuclear medicine parathyroid single-photon emission computed tomography (SPECT)/CT with technetium (Tc) 99m sestamibi found an abnormal nodular uptake within the left prevascular mediastinum suggestive of an ectopic parathyroid adenoma. A left-sided, video-assisted thoracoscopic surgery (VATS) with successful excision of the ectopic mediastinal parathyroid adenoma was performed. Surgical pathology revealed that the parathyroid adenoma was completely excised and surrounded by thymus and adipose tissue. The patient tolerated the procedure well and was discharged without further complications. The rarity of mediastinal, intrathymic parathyroid adenomas resulted in delayed diagnosis in this patient, understandably so as errant embryogenesis does not occur commonly. Visualization with SPECT/CT and successful specimen excision by minimally invasive VATS resulted in the accurate diagnosis and ultimate cure of this patient's primary hyperparathyroidism.

Multiple endocrine neoplasia type 1 familial case in a patient with insulinoma and primary hyperparathyroidism: First report in literature and in the Costa Rican population of the c.1224_1225insGTCC pathogenic variant

Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant disorder without a good genotype-phenotype correlation, characterized by tumor predisposition in the parathyroid gland, anterior pituitary, and pancreatic islet cells. Here, we describe a 37-year-old male with previous history of nephrolithiasis, with a 1-year history of recurrent hypoglycemic episodes. Physical examination revealed the presence of two lipomas. Family history revealed primary hyperparathyroidism (PHPT), hyperprolactinemia, and multiple non-functioning pancreatic neuroendocrine tumors. Initial laboratories revealed hypoglycemia and primary hyperparathyroidism. A fasting test was positive after 3 hours of initiation. An abdominal CT Scan demonstrated a 28 × 27 mm mass in the pancreatic tail and bilateral nephrolithiasis. A distal pancreatectomy was done. After surgery, the patient persisted with hypoglycemic episodes that were managed with diazoxide and frequent feedings. A parathyroid Tc-99 m MIBI scan with SPECT/CT imaging demonstrated two hot uptake lesions compatible with abnormally functioning parathyroid tissue. Surgical treatment was offered; however, the patient decided to postpone the procedure. Direct sequence analysis of MEN1 gene revealed heterozygosity for a pathogenic insertion c.1224_1225insGTCC (p.Cys409Valfs*41). DNA sequence analysis was done to six of his first-degree relatives. A sister with clinical diagnosis of MEN1 and a pre-symptomatic brother were positive for the same MEN1 variant. To our knowledge, this is the first report of a genetically confirmed case of MEN1 in our country and is the first report in literature of the c.1224_1225insGTCC variant related to a clinically affected family.

A Molecular Switch between Mammalian MLL Complexes Dictates Response to Menin-MLL Inhibition

Menin interacts with oncogenic MLL1-fusion proteins, and small molecules that disrupt these associations are in clinical trials for leukemia treatment. By integrating chromatin-focused and genome-wide CRISPR screens with genetic, pharmacologic, and biochemical approaches, we discovered a conserved molecular switch between the MLL1-Menin and MLL3/4-UTX chromatin-modifying complexes that dictates response to Menin-MLL inhibitors. MLL1-Menin safeguards leukemia survival by impeding the binding of the MLL3/4-UTX complex at a subset of target gene promoters. Disrupting the Menin-MLL1 interaction triggers UTX-dependent transcriptional activation of a tumor-suppressive program that dictates therapeutic responses in murine and human leukemia. Therapeutic reactivation of this program using CDK4/6 inhibitors mitigates treatment resistance in leukemia cells that are insensitive to Menin inhibitors. These findings shed light on novel functions of evolutionarily conserved epigenetic mediators like MLL1-Menin and MLL3/4-UTX and are relevant to understand and target molecular pathways determining therapeutic responses in ongoing clinical trials.

SIGNIFICANCE

Menin-MLL inhibitors silence a canonical HOX- and MEIS1-dependent oncogenic gene expression program in leukemia. We discovered a parallel, noncanonical transcriptional program involving tumor suppressor genes that are repressed in Menin-MLL inhibitor-resistant leukemia cells but that can be reactivated upon combinatorial treatment with CDK4/6 inhibitors to augment therapy responses. This article is highlighted in the In This Issue feature, p. 1.

Effect of Menin Deletion in Early Osteoblast Lineage on the Mineralization of an In Vitro 3D Osteoid-like Dense Collagen Gel Matrix

Bone has a complex microenvironment formed by an extracellular matrix (ECM) composed mainly of mineralized type I collagen fibres. Bone ECM regulates signaling pathways important in the differentiation of osteoblast-lineage cells, necessary for bone mineralization and in preserving tissue architecture. Compared to conventional 2D cell cultures, 3D in vitro models may better mimic bone ECM and provide an environment to support osteoblastic differentiation. In this study, a biomimetic 3D osteoid-like dense collagen gel model was used to investigate the role of the nuclear protein menin plays in osteoblastic differentiation and matrix mineralization. Previous in vitro and in vivo studies have shown that when expressed at later stages of osteoblastic differentiation, menin modulates osteoblastogenesis and regulates bone mass in adult mice. To investigate the role of menin when expressed at earlier stages of the osteoblastic lineage, conditional knockout mice in which the Men1 gene is specifically deleted early (i.e., at the level of the pluripotent mesenchymal stem cell lineage), where generated and primary calvarial osteoblasts were cultured in plastically compressed dense collagen gels for 21 days. The proliferation, morphology and differentiation of isolated seeded primary calvarial osteoblasts from knockout (Prx1-Cre; Men1f/f) mice were compared to those isolated from wild-type (Men1f/f) mice. Primary calvarial osteoblasts from knockout and wild-type mice did not show differences in terms of proliferation. However, in comparison to wild-type cells, primary osteoblast cells derived from knockout mice demonstrated deficient mineralization capabilities and an altered gene expression profile when cultured in 3D dense collagen gels. In summary, these findings indicate that when expressed at earlier stages of osteoblast differentiation, menin is important in maintaining matrix mineralization in 3D dense collagen gel matrices, in vitro.

Multiple endocrine neoplasia type 1 involving both the liver and lung: a case report

BACKGROUND

Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant tumor syndrome with a high degree of heterogeneity in clinical phenotypes, generally involving the parathyroid, anterior pituitary, and enteropancreas. In recent years, several new insights into the clinical features of MEN1 have been reported in the literature. However, it is not clear whether MEN1-associated primary tumors can occur in the liver.

CASE PRESENTATION

We report the case of a 52-year-old man with multiple endocrine neoplasia type 1 diagnosed by genetic sequencing. After uniportal thoracoscopic right middle lobectomy, laparoscopic radical resection of the liver tumors, and radiofrequency ablation of the parathyroid space, the parathyroid hormone level decreased from 177 pg/ml to a normal level (20 pg/ml). No local tumor recurrence was observed during a follow-up of 5 months.

CONCLUSION

We report the first case of MEN1 with simultaneous liver and lung involvement in which the patient underwent radical resection of the tumors, and we propose the possibility that the liver and other nonendocrine organs may also develop diseases associated with MEN1; although, this view needs further verification. Gene detection has crucial clinical significance for guiding diagnosis and treatment.

Beyond the "3 Ps": A critical appraisal of the non-endocrine manifestations of multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type 1 (MEN1), an autosomal-dominantly inherited tumor syndrome, is classically defined by tumors arising from the "3 Ps": Parathyroids, Pituitary, and the endocrine Pancreas. From its earliest descriptions, MEN1 has been associated with other endocrine and non-endocrine neoplastic manifestations. High quality evidence supports a direct association between pathogenic MEN1 variants and neoplasms of the skin (angiofibromas and collagenomas), adipose tissue (lipomas and hibernomas), and smooth muscle (leiomyomas). Although CNS tumors, melanoma, and, most recently, breast cancer have been reported as MEN1 clinical manifestations, the published evidence to date is not yet sufficient to establish causality. Well-designed, multicenter prospective studies will help us to understand better the relationship of these tumors to MEN1, in addition to verifying the true prevalence and penetrance of the well-documented neoplastic associations. Nevertheless, patients affected by MEN1 should be aware of these non-endocrine manifestations, and providers should be encouraged always to think beyond the "3 Ps" when treating an MEN1 patient.

Reduced menin expression leads to decreased ERα expression and is correlated with the occurrence of human luminal B-like and ER-negative breast cancer subtypes

Purpose

Menin, encoded by the MEN1 gene, was recently reported to be involved in breast cancers, though the underlying mechanisms remain elusive. In the current study, we sought to further determine its role in mammary cells.

Methods

Menin expression in mammary lesions from mammary-specific Men1 mutant mice was detected using immunofluorescence staining. RT-qPCR and western blot were performed to determine the role of menin in ERα expression in human breast cancer cell lines. ChIP-qPCR and reporter gene assays were carried out to dissect the action of menin on the proximal ESR1 promoter. Menin expression in female patients with breast cancer was analyzed and its correlation with breast cancer subtypes was investigated.

Results

Immunofluorescence staining revealed that early mammary neoplasia in Men1 mutant mice displayed weak ERα expression. Furthermore, MEN1 silencing led to both reduced ESR1 mRNA and ERα protein expression in MCF7 and T47D cells. To further dissect the regulation of ESR1 transcription by menin, we examined whether and in which way menin could regulate the proximal ESR1 promoter, which has not been fully explored. Using ChIP analysis and reporter gene assays covering − 2500 bp to + 2000 bp of the TSS position, we showed that the activity of the proximal ESR1 promoter was markedly reduced upon menin downregulation independently of H3K4me3 status. Importantly, by analyzing the expression of menin in 354 human breast cancers, we found that a lower expression was associated with ER-negative breast cancer (P = 0.041). Moreover, among the 294 ER-positive breast cancer samples, reduced menin expression was not only associated with larger tumors (P = 0.01) and higher SBR grades (P = 0.005) but also with the luminal B-like breast cancer subtype (P = 0.006). Consistent with our clinical data, we demonstrated that GATA3 and FOXA1, co-factors in ESR1 regulation, interact physically with menin in MCF7 cells, and MEN1 knockdown led to altered protein expression of GATA3, the latter being a known marker of the luminal A subtype, in MCF7 cells.

Conclusion

Taken together, our data provide clues to the important role of menin in ERα regulation and the formation of breast cancer subtypes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10549-021-06339-9.

Multiple endocrine neoplasia type 1 with a frameshift mutation in its gene accompanied by a giant cervical lipoma and multiple fatty deposits in the pancreas: case report

BACKGROUND

Multiple endocrine neoplasia type 1 (MEN1) is a syndrome characterized by pituitary neoplasia, primary hyperparathyroidism and pancreatic endocrine tumor. Here we show a case of MEN1 with a germline frameshift mutation in its gene accompanied by a giant cervical lipoma and multiple fatty deposits in the pancreas.

CASE PRESENTATION

A 28-year-old man noticed the decreased visual acuity of both eyes and visited our institution. Since he was diagnosed as visual disturbance and brain computer tomography (CT) showed a mass in the pituitary fossa, he was hospitalized in our institution. Endoscopic trans-sphenoidal hypophysectomy and total parathyroidectomy with auto-transplantation were performed, and a giant cervical lipoma was resected. Furthermore, in genetic search, we found a germline frameshift mutation in MEN1 gene leading to the appearance of a new stop codon.

CONCLUSIONS

We should bear in m ind that giant skin lipoma and multiple abnormal fatty deposits in the pancreas could be complicated with MEN1.

Multiple Endocrine Neoplasia Type 1 with Concomitant Existence of Malignant Insulinoma: A Rare Finding

Multiple endocrine neoplasia type 1 (MEN1) is a rare syndrome of autosomal dominant inheritance defined by co-occurrence of two or more tumors originating from the parathyroid gland, pancreatic islet cells, and/or anterior pituitary. Insulinoma which has an incidence of 0.4% is a rare pancreatic neuroendocrine tumor. Malignant insulinoma is extremely rare, while primary hyperparathyroidism is a common occurrence in MEN1. We present a case of MEN1 syndrome with 2.6 cm insulinoma in the pancreatic head and parathyroid adenoma in a 56-year-old female who presented with symptoms suggestive of hypoglycemia like multiple episodes of loss of consciousness for four years. Classical pancreaticoduodenectomy was carried out, and the postoperative period was uneventful. Later, subtotal parathyroidectomy was performed, which showed parathyroid adenoma. Patients presenting with features of hypoglycemia should be vigilantly assessed for the presence of a sinister pathology.

Role of miR-24 in Multiple Endocrine Neoplasia Type 1: A Potential Target for Molecular Therapy

Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant inherited multiple cancer syndrome of neuroendocrine tissues. Tumors are caused by an inherited germinal heterozygote inactivating mutation of the MEN1 tumor suppressor gene, followed by a somatic loss of heterozygosity (LOH) of the MEN1 gene in target neuroendocrine cells, mainly at parathyroids, pancreas islets, and anterior pituitary. Over 1500 different germline and somatic mutations of the MEN1 gene have been identified, but the syndrome is completely missing a direct genotype-phenotype correlation, thus supporting the hypothesis that exogenous and endogenous factors, other than MEN1 specific mutation, are involved in MEN1 tumorigenesis and definition of individual clinical phenotype. Epigenetic factors, such as microRNAs (miRNAs), are strongly suspected to have a role in MEN1 tumor initiation and development. Recently, a direct autoregulatory network between miR-24, MEN1 mRNA, and menin was demonstrated in parathyroids and endocrine pancreas, showing a miR-24-induced silencing of menin expression that could have a key role in initiation of tumors in MEN1-target neuroendocrine cells. Here, we review the current knowledge on the post-transcriptional regulation of MEN1 and menin expression by miR-24, and its possible direct role in MEN1 syndrome, describing the possibility and the potential approaches to target and silence this miRNA, to permit the correct expression of the wild type menin, and thereby prevent the development of cancers in the target tissues.

Multifocal pancreatic PPoma in the setting of MEN1: Case report and review of literature

Introduction and importance

Functioning pancreatic neuroendocrine tumors (pNETs) that express pancreatic polypeptide—PPomas—do not yet have a pathognomonic clinical syndrome associated with them due to their overall rarity and diverse symptoms. Moreover, in patients with MEN1, the often multifocal nature of pNETs presents a unique clinical issue.

Case presentation

We report a case of a 22-year-old man with a known MEN1 gene mutation who was suffering from severe diarrhea (7–8 bowel movements per day) and was found to have only elevated PP levels on biochemical work-up. Ga68-DOTATATE PET/CT showed multifocal tumors in the body and tail of the pancreas that were not evident on contrast-enhanced CT. The patient underwent a successful laparoscopic radical antegrade modular pancreatosplenectomy (RAMP) and recovered well post-operatively with complete resolution of his diarrhea. Immunohistochemistry showed multiple pure PPomas.

Clinical discussion

This case highlights the unique propensity for multifocal disease in patients with MEN1 mutations and the utility of functional imaging by somatostatin analogs, i.e., Ga68-DOTATATE PET/CT, in order to perform oncologic laparoscopic pancreatic resections.

Conclusion

PPomas in the setting of MEN1 mutations are a unique clinical entity due to their diverse associated clinical syndromes and propensity for multifocal disease.

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PPomas have no pathognomonic clinical syndrome associated with them.

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Patients with MEN1 have a propensity for multifocal pNETs.

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DOTATE PET/CT is vital adjunct to pancreatic protocol CT for operative planning.

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Intra-operative ultrasound makes laparoscopic multi-focal pNET resection feasible.

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DOTATATE PET/CT surveillance is necessary due to high risk for recurrence in MEN1.

Clinical Profile and Mutations Associated with Multiple Endocrine Neoplasia-Type1 (MEN1) and Their First-Degree Relatives at Risk of Developing MEN1: A Prospective Study

Multiple Endocrine Neoplasia type-1 (MEN1) is an autosomal dominant disorder with a combined occurrence of tumours of parathyroid glands, pancreatic islets, and anterior pituitary. About 90% of these patients carry mutations in the MEN1 gene, though the spectrum is not well defined in India. Forty clinically suspected cases of MEN1 were enrolled prospectively over six years; 32 patients (23 index-cases and nine affected relatives) with≥2 classical endocrine tumours of MEN1 were considered definite, and eight were categorised as 'MEN1-like'. Details of their clinical presentation, treatment and mutational analysis including MEN1 gene, 3' and 5' untranslated regions (UTR) of MEN1, CDKN1B, and CaSR genes were collated. Asymptomatic first-degree relatives were also screened. Among the 32 definite MEN1 patients, all had primary hyperparathyroidism, 22 (68.7%) had gastroentero-pancreatic neuroendocrine tumours, and 21 (66%) had pituitary adenoma. Of the 23 definite index-cases, 13 (56.5%) carried mutations in the MEN1 gene. Five of nine affected first-degree relatives (55.5%), and four of 10 asymptomatic relatives (40%) also had MEN1 mutations. Seven of 10 MEN1 mutation-negative definite index-cases harboured p.V109G polymorphism in the CDKN1B gene. All eight MEN1-like cases were negative for mutations and large deletions in MEN1, mutations in 3' and 5' UTR of MEN1, CaSR and CDKN1B genes. The study has helped to clearly document the pattern of mutations among Indian MEN1 patients. However, the absence of MEN1 mutation in ~44% of cases and the presence of p.V109G polymorphism in CDKN1B gene raise the question whether such polymorphisms could independently contribute to pathogenesis.

Patients' perception on the quality of care for multiple endocrine neoplasia disorders in Europe: an online survey from a patient support group

PURPOSE

European Patient Advocacy Groups (ePAGs) within the Endo-ERN identified a lack of knowledge about quality of care (QoC) of patients with multiple endocrine neoplasia (MEN). The aim of this study was to identify inequalities in care and to encourage improvements.

METHODS

The European MEN Alliance (EMENA) developed and conducted a survey, using the European Commissions' EUSurvey platform. Patient groups and healthcare professionals (HCPs) distributed the survey.

RESULTS

A total of 288 participants completed the survey (MEN1 n = 203, MEN2 n = 67, MEN3 n = 18) from 18 European countries. The majority of respondents were recruited via patient groups (58%), aged between 41 and 60 years (53%) and were female (67%). All participants reported having been diagnosed on average 5.58 years (95%-CI: 4.45-6.60) after first symptoms occurred. This timeframe was lower in the group with MEN2 (2.97 years, 95%-CI: 1.37-4.57). Most of the participants (67%) received their diagnosis by a positive gene test after presenting with one or more MEN-related tumours. Overall QoC was rated as either "good" (43%) or "excellent" (36%).

CONCLUSION

The results of this unique Europe-wide, patient-driven survey on QoC of patients with MEN show that ratings for overall QoC were lower than ratings for different aspects of care. This may be because of the complex nature of care for genetic syndromes. Furthermore, patients who connect with patient groups may be deemed "expert patients" whose answers are not representative of the overall MEN patient community. We hope that Endo-ERN can support further education and training for HCPs based on these results.

Phenotypes Associated With MEN1 Syndrome: A Focus on Genotype-Phenotype Correlations

Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant inherited tumor syndrome, associated with parathyroid, pituitary, and gastro-entero-pancreatic (GEP) neuroendocrine tumors (NETs). MEN1 is usually consequent to different germline and somatic mutations of the MEN1 tumor suppressor gene, although phenocopies have also been reported. This review analyzed main biomedical databases searching for reports on MEN1 gene mutations and focused on aggressive and aberrant clinical manifestations to investigate the potential genotype-phenotype correlation. Despite efforts made by several groups, this link remains elusive to date and evidence that aggressive or aberrant clinical phenotypes may be related to specific mutations has been provided by case reports and small groups of MEN1 patients or families. In such context, a higher risk of aggressive tumor phenotypes has been described in relation to frameshift and non-sense mutations, and predominantly associated with aggressive GEP NETs, particularly pancreatic NETs. In our experience a novel heterozygous missense mutation at c.836C>A in exon 6 was noticed in a MEN1 patient operated for macro-prolactinoma, who progressively developed recurrent parathyroid adenomas, expanding gastrinomas and, long after the first MEN1 manifestation, a neuroendocrine uterine carcinoma. In conclusion, proof of genotype-phenotype correlation is limited but current evidence hints at the need for long-term interdisciplinary surveillance in patients with aggressive phenotypes and genetically confirmed MEN1.

MiR-24-3p regulates cell proliferation and milk protein synthesis of mammary epithelial cells through menin in dairy cows

MiR-24-3p, a broadly conserved, small, noncoding RNA, is abundantly expressed in mammary tissue. However, its regulatory role in this tissue remains poorly understood. It was predicted that miR-24-3p targets the 3' untranslated region (3'-UTR) of multiple endocrine neoplasia type 1 (MEN1), an important regulatory factor in mammary tissue. The objective of this study was to investigate the function of miR-24-3p in mammary cells. Using a luciferase assay in mammary epithelial cells (MAC-T), miR-24-3p was confirmed to target the 3'-UTR of MEN1. Furthermore, miR-24-3p negatively regulated the expression of the MEN1 gene and its encoded protein, menin. miR-24-3p enhanced proliferation of MAC-T by promoting G1/S phase progression. MiR-24-3p also regulated the expression of key factors involved in phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin and Janus kinase/signal transducer and activators of transcription signaling pathways, therefore controlling milk protein synthesis in epithelial cells. Thus, miR-24-3p appears to act on MAC-T by targeting MEN1. The expression of miR-24-3p was controlled by MEN1/menin, indicating a negative feedback loop between miR-24-3p and MEN1/menin. The negatively inhibited expression pattern of miR-24-3p and MEN1 was active in mammary tissues at different lactation stages. The feedback mechanism is a new concept to further understand the lactation cycle of mammary glands and can possibly to be manipulated to improve milk yield and quality.

Multiple Endocrine Neoplasia Type 1 (MEN1): An Update and the Significance of Early Genetic and Clinical Diagnosis

Multiple endocrine neoplasia type 1 (MEN1) is a rare hereditary tumor syndrome inherited in an autosomal dominant manner and characterized by a predisposition to a multitude of endocrine neoplasms primarily of parathyroid, enteropancreatic, and anterior pituitary origin, as well as nonendocrine neoplasms. Other endocrine tumors in MEN1 include foregut carcinoid tumors, adrenocortical tumors, and rarely pheochromocytoma. Nonendocrine manifestations include meningiomas and ependymomas, lipomas, angiofibromas, collagenomas, and leiomyomas. MEN1 is caused by inactivating mutations of the tumor suppressor gene MEN1 which encodes the protein menin. This syndrome can affect all age groups, with 17% of patients developing MEN1-associated tumors before 21 years of age. Despite advances in the diagnosis and treatment of MEN1-associated tumors, patients with MEN1 continue to have decreased life expectancy primarily due to malignant neuroendocrine tumors. The most recent clinical practice guidelines for MEN1, published in 2012, highlight the need for early genetic and clinical diagnosis of MEN1 and recommend an intensive surveillance approach for both patients with this syndrome and asymptomatic carriers starting at the age of 5 years with the goal of timely detection and management of MEN1-associated neoplasms and ultimately decreased disease-specific morbidity and mortality. Unfortunately, there is no clear genotype-phenotype correlation and individual mutation-dependent surveillance is not possible currently.

Children with MEN1 gene mutations may present first (and at a young age) with Cushing disease

OBJECTIVE

Cushing disease (CD) is a rare entity caused by ACTH-secreting pituitary tumours, leading to prolonged hypercortisolism. Most cases are sporadic but can rarely occur in the context of familial predisposition, due to germline mutations in genes such as MEN1, leading to multiple endocrine neoplasia type 1, MEN1. We have reported previously that CD can be the first and only presenting manifestation of MEN1. In this report, we describe a cohort of paediatric patients who presented with CD as the first manifestation of MEN1.

MATERIALS AND METHODS

A retrospective analysis of paediatric patients admitted to the National Institutes of Health (NIH) Clinical Center for evaluation of hypercortisolism, between 1997 and 2017. MEN1 was diagnosed on a clinical, familial and/or genetic basis.

RESULTS

Of a total of 238 children with CD, six patients were subsequently diagnosed with MEN1, three males and three females with a mean age at diagnosis of CD at 13.4 ± 2.9 years. Five of the six patients had familial MEN1 and one patient was a sporadic case. Additional manifestations of MEN1 included primary hyperparathyroidism in three patients and hyperprolactinemia in two patients.

DISCUSSION

This report describes a paediatric patient population with MEN1 in whom CD was the initial manifestation, confirming a previous observation that paediatric patients with MEN1 may present first with an ACTH-producing adenoma. Therefore, germline MEN1 mutations should be sought in paediatric CD and tested for when there is a suggestive family history and/or other manifestations.

PPoma Review: Epidemiology, Aetiopathogenesis, Prognosis and Treatment

Generally, pancreatic polypeptide-secreting tumor of the distal pancreas (PPoma) is classified as a rare tumor, and may occur sporadically or be associated in families or with multiple endocrine neoplasia type 1 (NEM 1). It grows slowly, reaching large dimensions at the time of diagnosis and the symptomatology is fundamentally due to the mass effect, causing either non-specific abdominal pain or symptoms suggestive of obstruction of the pancreatic or biliary duct. Therefore, when detected, they are usually malignant, with metastases mainly in the liver. The combination of serum analysis of increased levels of chromogranin A and pancreatic polypeptide and pancreastatin is very useful with a sensitivity of up to 95%. However, in addition, scintigraphicexams with somatostatin analogues should be performed to better clarify the diagnosis. Surgical resection is the treatment of choice, despite surgical difficulty and because they are generally palliative due to the metastases. Surgeries for tumor volume reduction are also performed to relieve symptoms. Chemotherapy commonly uses streptozotocin and somatostatin analogues to treat residual disease. Unfortunately, the survival rates are still very low, less than 10%, and if metastases already exist, this percentage drops to 3%.

When should genetic testing be performed in patients with neuroendocrine tumours?

Neuroendocrine tumours (NETs) are a heterogenous group of tumours arising from neuroendocrine cells in several sites around the body. They include tumours of the gastroenteropancreatic system, phaeochromocytoma and paraganglioma and medullary thyroid cancer. In recent years, it has become increasingly apparent that a number of these tumours arise as a result of germline genetic mutations and are inherited in an autosomal dominant pattern. The number of genes implicated is increasing rapidly. Identifying which patients are likely to have a germline mutation enables clinicians to counsel patients adequately about their future disease risk, and allows for earlier detection of at-risk patients through family screening. The institution of screening and surveillance programmes may in turn lead to a major shift in presentation patterns for some of these tumours. In this review, we examine the features which may lead a clinician to suspect that a patient may have an inherited cause of a NET and we outline which underlying conditions should be suspected. We also discuss what type of screening may be appropriate in a variety of situations.

Multiple endocrine neoplasia syndrome type 1: institution, management, and data analysis of a nationwide multicenter patient database

OBJECTIVE

The aim of this study was to integrate European epidemiological data on patients with multiple endocrine neoplasia type 1 by creating an Italian registry of this syndrome, including clinical and genetic characteristics and therapeutic management.

METHODS

Clinical, familial and genetic data of patients with multiple endocrine neoplasia type 1, diagnosed, treated, and followed-up for a mean time of 11.3 years, in 14 Italian referral endocrinological centers, were collected, over a 3-year course (2011-2013), to build a national electronic database.

RESULTS

The Italian multiple endocrine neoplasia type 1 database includes 475 patients (271 women and 204 men), of whom 383 patients (80.6%) were classified as familial cases (from 136 different pedigrees), and 92 (19.4%) patients were sporadic cases. A MEN1 mutation was identified in 92.6% of familial cases and in 48.9% of sporadic cases. Four hundred thirty-six patients were symptomatic, presenting primary hyperparathyroidism, gastroenteropancreatic neuroendocrine tumors and pituitary tumors in 93, 53, and 41% of cases, respectively. Thirty-nine subjects, belonging to affected pedigrees positive for a MEN1 mutation, were asymptomatic at clinical and biochemical screening. Age at diagnosis of multiple endocrine neoplasia type 1 probands was similar for both familial and simplex cases (mean age 47.2 ± 15.3 years). In familial cases, diagnosis of multiple endocrine neoplasia type 1 in relatives of affected probands was made more than 10 years in advance (mean age at diagnosis 36.5 ± 17.6 years).

CONCLUSIONS

The analysis of Italian registry of multiple endocrine neoplasia type 1 patients revealed that clinical features of Italian multiple endocrine neoplasia type 1 patients are similar to those of other western countries, and confirmed that the genetic test allowed multiple endocrine neoplasia type 1 diagnosis 10 years earlier than biochemical or clinical diagnosis.

Deletion of Menin in craniofacial osteogenic cells in mice elicits development of mandibular ossifying fibroma

Ossifying fibroma (OF) is a rare benign tumor of the craniofacial bones that can reach considerable and disfiguring dimensions if left untreated. Although the clinicopathological characteristics of OF are well established, the underlying etiology has remained largely unknown. Our work indicates that Men1-a tumor suppressor gene responsible of Multiple endocrine neoplasia type 1-is critical for OF formation and shows that mice with targeted disruption of Men1 in osteoblasts (Men1^Runx2Cre) develop multifocal OF in the mandible with a 100% penetrance. Using lineage-tracing analysis, we demonstrate that loss of Men1 arrests stromal osteoprogenitors in OF at the osterix-positive pre-osteoblastic differentiation stage. Analysis of Men1-lacking stromal spindle cells isolated from OF (OF-derived MSCs (OFMSCs)) revealed a downregulation of the cyclin-dependent kinase (CDK) inhibitor Cdkn1a, consistent with an increased proliferation rate. Intriguingly, the re-expression of Men1 in Men1-deficient OFMSCs restored Cdkn1a expression and abrogated cellular proliferation supporting the tumor-suppressive role of Men1 in OF. Although our work presents the first evidence of Men1 in OF development, it further provides the first genetic mouse model of OF that can be used to better understand the molecular pathogenesis of these benign tumors and to potentially develop novel treatment strategies.

Animal models of MEN1

Animal models of cancer have been instrumental in advancing our understanding of the biology of tumor initiation and progression, in studying gene function and in performing preclinical studies aimed at testing novel therapies. Several animal models of the MEN1 syndrome have been generated in different organisms by introducing loss-of-function mutations in the orthologues of the human MEN1 gene. In this review, we will discuss MEN1 and MEN1-like models in Drosophila, mice and rats. These model systems with their specific advantages and limitations have contributed to elucidate the function of Menin in tumorigenesis, which turned out to be remarkably conserved from flies to mammals, as well as the biology of the disease. Mouse models of MEN1 closely resemble the human disease in terms of tumor spectrum and associated hormonal changes, although individual tumor frequencies are variable. Rats affected by the MENX (MEN1-like) syndrome share some features with MEN1 patients albeit they bear a germline mutation in Cdkn1b (p27) and not in Men1 Both Men1-knockout mice and MENX rats have been exploited for therapy-response studies testing novel drugs for efficacy against neuroendocrine tumors (NETs) and have provided promising leads for novel therapies. In addition to presenting well-established models of MEN1, we also discuss potential models which, if implemented, might broaden even further our knowledge of neuroendocrine tumorigenesis. In the future, patient-derived xenografts in zebrafish or mice might allow us to expand the tool-box currently available for preclinical studies of MEN1-associated tumors.

An autoregulatory network between menin and pri-miR-24-1 is required for the processing of its specific modulator miR-24-1 in BON1 cells

Multiple endocrine neoplasia type 1 (MEN1) is a rare hereditary cancer complex syndrome manifesting a variety of endocrine and non-endocrine neoplasms and lesions. MEN1 is characterized by tumours of the parathyroids, of the neuroendocrine cells of the gastroenteropancreatic tract, and of the anterior pituitary. The MEN1 gene, a tumour suppressor gene, encodes the menin protein. Loss of heterozygosity (LOH) at 11q13 is typical of MEN1 tumours in agreement with Knudson's two-hit hypothesis. We previously showed that the MEN1 parathyroid tumorigenesis is under the control of an "incoherent feedback loop" between miR-24-1 and the menin protein that generates a "Gene Regulatory Network" (GRN) that mimics the second hit of Knudson's hypothesis and that could buffer the effect of the stochastic factors that contribute to the onset and progression of this disease. Here we show, in the BON1 cell line derived from lymphnode metastasis of a human carcinoid tumour of the pancreas, that menin binds specifically to the primary RNA sequence pri-miR-24-1 by promoting the miR-24-1 biogenesis. Network simulation showed a new feed-forward loop between menin, microRNA-24-1 and Musashi-1 proteins. This result shows a novel mechanism whereby menin, a RNA-binding protein, facilitates the processing of its specific miRNA by regulating the dynamics of the menin-miR-24 Gene Regulatory Network at the level of pri-miRNA processing.

Whole-Genome Sequence of the Metastatic PC3 and LNCaP Human Prostate Cancer Cell Lines

The bone metastasis-derived PC3 and the lymph node metastasis-derived LNCaP prostate cancer cell lines are widely studied, having been described in thousands of publications over the last four decades. Here, we report short-read whole-genome sequencing (WGS) and de novo assembly of PC3 (ATCC CRL-1435) and LNCaP (clone FGC; ATCC CRL-1740) at ∼70 × coverage. A known homozygous mutation in TP53 and homozygous loss of PTEN were robustly identified in the PC3 cell line, whereas the LNCaP cell line exhibited a larger number of putative inactivating somatic point and indel mutations (and in particular a loss of stop codon events). This study also provides preliminary evidence that loss of one or both copies of the tumor suppressor Capicua (CIC) contributes to primary tumor relapse and metastatic progression, potentially offering a treatment target for castration-resistant prostate cancer (CRPC). Our work provides a resource for genetic, genomic, and biological studies employing two commonly-used prostate cancer cell lines.

Identification, genetic testing, and management of hereditary melanoma

Several distinct melanoma syndromes have been defined, and genetic tests are available for the associated causative genes. Guidelines for melanoma genetic testing have been published as an informal "rule of twos and threes," but these guidelines apply to CDKN2A testing and are not intended for the more recently described non-CDKN2A melanoma syndromes. In order to develop an approach for the full spectrum of hereditary melanoma patients, we have separated melanoma syndromes into two types: "melanoma dominant" and "melanoma subordinate." Syndromes in which melanoma is a predominant cancer type are considered melanoma dominant, although other cancers, such as mesothelioma or pancreatic cancers, may also be observed. These syndromes are associated with defects in CDKN2A, CDK4, BAP1, MITF, and POT1. Melanoma-subordinate syndromes have an increased but lower risk of melanoma than that of other cancer(s) seen in the syndrome, such as breast and ovarian cancer or Cowden syndrome. Many of these melanoma-subordinate syndromes are associated with well-established predisposition genes (e.g., BRCA1/2, PTEN). It is likely that these predisposition genes are responsible for the increased susceptibility to melanoma as well but with lower penetrance than that observed for the dominant cancer(s) in those syndromes. In this review, we describe our extension of the "rule of twos and threes" for melanoma genetic testing. This algorithm incorporates an understanding of the spectrum of cancers and genes seen in association with melanoma to create a more comprehensive and tailored approach to genetic testing.

Oncocytic Adrenocortical Neoplasm with Concomitant Papillary Thyroid Cancer

Adrenal oncocytoma (AO) is an extremely rare adrenocortical neoplasm and little is known about its malignant potential, secretory properties, and hereditary origin. We present the case of a benign AO with concomitant incidentally found papillary thyroid cancer (PTC) and review similar cases in the literature. Immunohistochemistry and next-generation sequencing (NGS) were performed. A 66-year-old women was incidentally found to have a large, androgen-secreting right adrenal mass. ¹⁸F-Fluorodeoxyglucose positron emission tomography showed intense uptake (SUV_max 88.7) of this mass and found a hypermetabolic right thyroid mass. Open adrenalectomy was performed for this highly suspicious adrenal mass. Histopathology revealed benign AO that was BRAF^V600E negative, with low Ki-67, and no somatic mutation found on NGS. Thyroidectomy revealed invasive, BRAF^V600E-positive PTC. At 6 months follow-up, androgen levels returned to normal, and no recurrence was seen on imaging. To our knowledge, this is the first report of an androgen-secreting AO with concomitant PTC. Possibly the simultaneous discovery of two independent neoplasms was observed. In conclusion, this case highlights that care should be given to exclude concomitant neoplasms. Long-term and regular imaging with biochemical follow-up is warranted, since the outcome and clinical behavior of AO remains uncertain.

Novel insights into the polycythemia-paraganglioma-somatostatinoma syndrome

Worldwide, the syndromes of paraganglioma (PGL), somatostatinoma (SOM) and early childhood polycythemia are described in only a few patients with somatic mutations in the hypoxia-inducible factor 2 alpha (HIF2A). This study provides detailed information about the clinical aspects and course of 7 patients with this syndrome and brings into perspective these experiences with the pertinent literature. Six females and one male presented at a median age of 28 years (range 11-46). Two were found to have HIF2A somatic mosaicism. No relatives were affected. All patients were diagnosed with polycythemia before age 8 and before PGL/SOM developed. PGLs were found at a median age of 17 years (range 8-38) and SOMs at 29 years (range 22-38). PGLs were multiple, recurrent and metastatic in 100, 100 and 29% of all cases, and SOMs in 40, 40 and 60%, respectively. All PGLs were primarily norepinephrine-producing. All patients had abnormal ophthalmologic findings and those with SOMs had gallbladder disease. Computed tomography (CT) and magnetic resonance imaging revealed cystic lesions at multiple sites and hemangiomas in 4 patients (57%), previously thought to be pathognomonic for von Hippel-Lindau disease. The most accurate radiopharmaceutical to detect PGL appeared to be [¹⁸F]-fluorodihydroxyphenylalanine ([¹⁸F]-FDOPA). Therefore, [¹⁸F]-FDOPA PET/CT, not [⁶⁸Ga]-(DOTA)-[Tyr3]-octreotate ([⁶⁸Ga]-DOTATATE) PET/CT is recommended for tumor localization and aftercare in this syndrome. The long-term prognosis of the syndrome is unknown. However, to date no deaths occurred after 6 years follow-up. Physicians should be aware of this unique syndrome and its diagnostic and therapeutic challenges.

New Insights Into the Mechanism of COP9 Signalosome-Cullin-RING Ubiquitin-Ligase Pathway Deregulation in Urological Cancers

Urological cancers are a very common type of cancer worldwide and have alarming high incidence and mortality rates, especially in kidney cancers, illustrate the urgent need for new therapeutic targets. Recent publications point to a deregulated COP9 signalosome (CSN)-cullin-RING ubiquitin-ligase (CRL) pathway which is here considered and investigated as potential target in urological cancers with strong focus on renal cell carcinomas (RCC). The CSN forms supercomplexes with CRLs in order to preserve protein homeostasis and was found deregulated in several cancer types. Examination of selected CSN-CRL pathway components in RCC patient samples and four RCC cell lines revealed an interesting deregulated p27(Kip1)-Skp2-CAND1 axis and two p27(Kip1) point mutations in 786-O cells; p27(Kip1)V109G and p27(Kip1)I119T. The p27(Kip1) mutants were detected in patients with RCC and appear to be responsible for an accelerated growth rate in 786-O cells. The occurrence of p27(Kip1)V109G and p27(Kip1)I119T in RCC makes the CSN-CRL pathway an attractive therapeutic target.

Diagnosis and Management of Hereditary Adrenal Cancer

Benign adrenocortical tumours (ACT) are relatively frequent lesions; on the contrary, adrenocortical carcinoma (ACC) is a rare and aggressive malignancy with unfavourable prognosis. Recent advances in the molecular understanding of adrenal cancer offer promise for better therapies in the future. Many of these advances stem from the molecular elucidation of genetic conditions predisposing to the development of ACC. Six main clinical syndromes have been described to be associated with hereditary adrenal cancer. In these conditions, genetic counselling plays an important role for the early detection and follow-up of the patients and the affected family members.

Familial Endocrine Syndromes

Endocrine tumors may present as sporadic events or as part of familial endocrine syndromes. Familial endocrine syndromes (or inherited tumor/neoplasm syndromes) are characterized by multiple tumors in multiple organs. Some morphologic findings in endocrine tumor histopathology may prompt the possibility of familial endocrine syndromes, and these recognized histologic features may lead to further molecular genetic evaluation of the patient and family members. Subsequent evaluation for these syndromes in asymptomatic patients and family members may then be performed by genetic screening.

Menin: a tumor suppressor that mediates postsynaptic receptor expression and synaptogenesis between central neurons of Lymnaea stagnalis

Neurotrophic factors (NTFs) support neuronal survival, differentiation, and even synaptic plasticity both during development and throughout the life of an organism. However, their precise roles in central synapse formation remain unknown. Previously, we demonstrated that excitatory synapse formation in Lymnaea stagnalis requires a source of extrinsic NTFs and receptor tyrosine kinase (RTK) activation. Here we show that NTFs such as Lymnaea epidermal growth factor (L-EGF) act through RTKs to trigger a specific subset of intracellular signalling events in the postsynaptic neuron, which lead to the activation of the tumor suppressor menin, encoded by Lymnaea MEN1 (L-MEN1) and the expression of excitatory nicotinic acetylcholine receptors (nAChRs). We provide direct evidence that the activation of the MAPK/ERK cascade is required for the expression of nAChRs, and subsequent synapse formation between pairs of neurons in vitro. Furthermore, we show that L-menin activation is sufficient for the expression of postsynaptic excitatory nAChRs and subsequent synapse formation in media devoid of NTFs. By extending our findings in situ, we reveal the necessity of EGFRs in mediating synapse formation between a single transplanted neuron and its intact presynaptic partner. Moreover, deficits in excitatory synapse formation following EGFR knock-down can be rescued by injecting synthetic L-MEN1 mRNA in the intact central nervous system. Taken together, this study provides the first direct evidence that NTFs functioning via RTKs activate the MEN1 gene, which appears sufficient to regulate synapse formation between central neurons. Our study also offers a novel developmental role for menin beyond tumour suppression in adult humans.

A rare case of hypoglycaemia due to insulinoma in an adolescent with acutely altered mental status

BACKGROUND

Multiple endocrine neoplasia type 1 (MEN1) is an inherited neoplasia syndrome that generally presents with hypercalcaemia due to hyperparathyroidism. Insulin-producing tumours are less common components of the syndrome that emerge later during the course of the disease. We report here a case of an adolescent who presented with symptomatic hypoglycaemia as the first indication of MEN1.

CASE

A 14-year-old boy, known to use illicit drugs, was brought to the hospital with altered mental status. He was hypoglycaemic and further investigations revealed two pancreatic insulinomas. Despite having no relevant family history, genetic evaluation showed a mutation consistent with MEN1.

CONCLUSION

Insulinomas in adolescents are generally rare and even less common as a first presentation of MEN1. This diagnosis carries implications for potential future neoplasms, both benign and malignant. While intoxication is a more common case of altered mental status in adolescents, clinicians must maintain a high index of suspicion for organic disease.

Familial pituitary tumors

Pituitary adenomas are benign intracranial neoplasms that present a major clinical concern due to hormone overproduction and/or tumor mass effects. The majority of pituitary adenomas occur sporadically; however, familial cases are increasingly being recognized, such as multiple endocrine neoplasia type 1 (MEN1), Carney complex (CNC), and familial isolated pituitary adenoma (FIPA). Familial pituitary tumors appear to differ from their sporadic counterparts both in their genetic basis and in clinical characteristics. Evidence suggests that, especially in MEN1 and FIPA, tumors are more aggressive and affect patients at a younger age, therefore justifying the importance of early diagnosis, while in Carney complex pituitary hyperplasia is common. The genetic alterations responsible for the formation of familial pituitary syndromes include the MEN1 gene, responsible for about 80% of MEN1 cases, the regulatory subunit of the protein kinase A, PRKAR1A, responsible for about 70% of Carney complex cases, and AIP, the gene coding the aryl hydrocarbon receptor interacting protein, responsible for about 20% of FIPA cases. Rarely other genes have also been found responsible for familial pituitary adenoma cases. McCune-Albright syndrome (MAS) also has a genetic origin due to mosaic mutations in the G protein-coupled α subunit coded by the GNAS1 gene. In this chapter, we summarize the genetic and clinical characteristics of these familial pituitary syndromes and MAS.

A differential diagnosis of inherited endocrine tumors and their tumor counterparts

Inherited endocrine tumors have been increasingly recognized in clinical practice, although some difficulties still exist in differentiating these conditions from their sporadic endocrine tumor counterparts. Here, we list the 12 main topics that could add helpful information and clues for performing an early differential diagnosis to distinguish between these conditions. The early diagnosis of patients with inherited endocrine tumors may be performed either clinically or by mutation analysis in at-risk individuals. Early detection usually has a large impact in tumor management, allowing preventive clinical or surgical therapy in most cases. Advice for the clinical and surgical management of inherited endocrine tumors is also discussed. In addition, recent clinical and genetic advances for 17 different forms of inherited endocrine tumors are briefly reviewed.

Risk factors for the occurrence of insulinoma: a case-control study

BACKGROUND

The etiology of insulinoma is poorly understood. Few studies investigated the possible roles of environmental factors and lifestyle in the pathogenesis of insulinoma. The aim of this study is to identify risk factors associated with occurrence of insulinoma in the Chinese population.

METHODS

This study consisted of 196 patients with insulinoma and 233 controls. Demographic information of the patients and controls and risk factors of the disease were analyzed. Univariate and unconditional multivariable logistic regression analyses were made to estimate odds ratios (ORs) and possible risk factors.

RESULTS

Approximately 68.88% (135/196) of the patients were from rural areas in contrast to 10.30% (24/233) of the controls (P<0.0001). This difference was confirmed by the multivariate analysis (OR=4.950; 95% CI: 2.928-8.370). Family history of pancreatic endocrine tumor (OR=16.754; 95% CI: 2.125-132.057) and other cancers (OR=2.360; 95% CI: 1.052-5.291) was also related to a high-risk population of insulinoma.

CONCLUSION

Rural residents or people who have a family history of pancreatic endocrine tumor and other cancers are a high-risk population of insulinoma.

Familial isolated pituitary adenomas: an emerging clinical entity

Familial pituitary tumors are increasingly recognized. While some of these cases are related to wellknown syndromic conditions such as multiple endocrine neoplasia type 1 (MEN1) or Carney complex, others belong to the familial isolated pituitary adenoma (FIPA) patient group. The discovery of heterozygous, loss-of-function germline mutations in the gene encoding the aryl hydrocarbon receptor interacting protein (AIP) in 2006 has subsequently enabled the identification of a mutation in this gene in 20% of FIPA families and 20% of childhood-onset simplex soma- totroph adenomas. The exact mechanism by which the lack of AIP leads to pituitary adenomas is not clear. AIP mutations cause a low penetrance autosomal dominant disease with often a distinct phenotype characterized by young-onset, aggressive, large GH, mixed GH and PRL or PRL-secreting adenomas. This review aims to summarize currently available clinical data on AIP mutation-positive and negative FIPA patients.

The negative feedback-loop between the oncomir Mir-24-1 and menin modulates the Men1 tumorigenesis by mimicking the "Knudson's second hit"

Multiple endocrine neoplasia type 1 (MEN1) syndrome is a rare hereditary cancer disorder characterized by tumors of the parathyroids, of the neuroendocrine cells, of the gastro-entero-pancreatic tract, of the anterior pituitary, and by non-endocrine neoplasms and lesions. MEN1 gene, a tumor suppressor gene, encodes menin protein. Loss of heterozygosity at 11q13 is typical of MEN1 tumors, in agreement with the Knudson’s two-hit hypothesis. In silico analysis with Target Scan, Miranda and Pictar-Vert softwares for the prediction of miRNA targets indicated miR-24-1 as capable to bind to the 3′UTR of MEN1 mRNA. We investigated this possibility by analysis of miR-24-1 expression profiles in parathyroid adenomatous tissues from MEN1 gene mutation carriers, in their sporadic non-MEN1 counterparts, and in normal parathyroid tissue. Interestingly, the MEN1 tumorigenesis seems to be under the control of a “negative feedback loop” between miR-24-1 and menin protein, that mimics the second hit of Knudson’s hypothesis and that could buffer the effect of the stochastic factors that contribute to the onset and progression of this disease. Our data show an alternative way to MEN1 tumorigenesis and, probably, to the “two-hit dogma”. The functional significance of this regulatory mechanism in MEN1 tumorigenesis is also the basis for opening future developments of RNA antagomir(s)-based strategies in the in vivo control of tumorigenesis in MEN1 carriers.