Breast-cancer predisposition in multiple endocrine neoplasia type 1

Importance of early detection in multiple endocrine neoplasia type 1: Clinical insights and future directions

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal-inherited syndrome involving multiple endocrine tumors. It is characterized by multiple mutations in the tumor suppressor gene MEN1, which is located on chromosome 11q13. As main etiology of MEN1 is genetic mutations, clinical symptoms may vary. In this editorial, we comment on the article by Yuan et al. This article describes a case of (MEN1) characterized by low incidence and diagnostic complexity. MEN1 commonly presents as parathyroid, pancreatic, and pituitary tumors. Diagnosis requires a combination of serologic tests, magnetic resonance imaging, computed tomography, endoscopic ultrasonography, immunologic and pathology. The diagnosis is unique depending on the site of disease. Surgical resection is the treatment of choice for MEN1. The prognosis depends on the site of origin, but early detection and intervention is the most effective.

American Association of Clinical Endocrinology Consensus Statement on Management of Multiple Endocrine Neoplasia Type 1

OBJECTIVE

This document presents the findings of the American Association of Clinical Endocrinology (AACE) on the diagnosis, management, and surveillance of patients with multiple endocrine neoplasia type 1 (MEN1) and associated tumors. The task force included a diverse group of experts in endocrinology, oncology, genetics, surgery, and patient representation. A comprehensive literature review was conducted to address key issues related to the evaluation, surveillance, and treatment of MEN1-related tumors.

METHODS

The task force, comprised of 9 members with expertise in endocrinology, surgery, medical oncology, genetics, and patient advocacy, collaborated to develop guidance for the evaluation, surveillance, and management of MEN1-associated tumors. Consensus was defined as ≤1 dissenting vote and significant majority as ≥75%. Relevant studies were identified through a literature review process, and consensus statements were based on the available evidence.

RESULTS

The task force deliberated on the surveillance, evaluation, and management of MEN1-related tumors including parathyroid, pituitary, and gastroenteropancreatic neuroendocrine tumors and other tumors of relevance. The document also addresses the indications for MEN1 genetic testing.

CONCLUSIONS

This consensus statement aims to offer evidence-informed guidance for health care providers involved in the care of patients with MEN1 and associated tumors. It provides guidance on diagnostic tools, genetic testing criteria, imaging techniques, surgical interventions, and posttreatment monitoring. The practical, patient-centered approach outlined in this document is intended to improve outcomes for individuals with MEN1 and other high-risk endocrine tumors.

Breast Cancer Risk and Management in the Endocrine Clinic: A Comprehensive Review

OBJECTIVE

This review seeks to provide endocrine clinicians with a comprehensive analysis of breast cancer risk, diagnostic modalities and management strategies in women with endocrine disorders, with particular emphasis on the influence of metabolic factors such as diabetes and obesity, and the role of Menopausal Hormone Therapy (MHT).

DESIGN

The review examines a spectrum of endocrine disorders commonly encountered in clinical practice, including Multiple Endocrine Neoplasia Types 1 (MEN1), 2 (MEN2) and 4 (MEN4), Von Hippel-Lindau syndrome (VHL), Pheochromocytoma and Paraganglioma (PPGL), Acromegaly, Hyperprolactinaemia, Polycystic Ovary Syndrome (PCOS), Congenital Adrenal Hyperplasia (CAH), Turner Syndrome, alongside metabolic conditions such as diabetes and obesity and the effects of MHT. The review critically appraises each disorder's association with breast cancer risk, screening implications and therapeutic management.

PATIENTS

This analysis focuses on women with the aforementioned endocrine and metabolic disorders, assessing their specific breast cancer risk profiles, informed by the latest clinical evidence and molecular insights.

MEASUREMENTS

The review comprehensively evaluates current evidence-based approaches to screening, diagnostic accuracy and treatment in this patient cohort. Emphasis is placed on the metabolic derangements, hormonal influences and genetic predispositions that modulate breast cancer risk, providing disorder-specific recommendations for individualised care.

RESULTS

The findings indicate a significantly elevated breast cancer risk in patients with MEN1, necessitating early initiation of MRI screening by age 40. In MEN2, emerging evidence suggests that combining RET inhibitors with endocrine therapy may yield clinical benefits, although further research is needed to validate this approach. The breast cancer risk associated with MEN4 and VHL syndromes, while documented, remains less well-characterised, requiring further investigation. Diabetes and obesity are confirmed as major modifiable risk factors, particularly in postmenopausal women, where hyperinsulinemia and metabolic dysfunction contribute to increased incidence and poorer outcomes, notably in triple-negative breast cancer (TNBC). The role of MHT, particularly combined oestrogen-progestogen therapy, is strongly associated with increased breast cancer risk, particularly for hormone receptor-positive malignancies, necessitating cautious use and personalised treatment planning. In contrast, oestrogen-only MHT appears to confer a reduced risk in women post-hysterectomy. For patients with PCOS, CAH and Turner Syndrome, while definitive evidence of elevated breast cancer risk is lacking, individualised screening strategies and careful hormone therapy management remain essential due to the complex interplay of hormonal and metabolic factors.

CONCLUSIONS

The review highlights the need for personalised breast cancer screening and management protocols in women with endocrine and metabolic disorders. For high-risk groups such as MEN1 patients, early initiation of MRI screening is warranted. In women with diabetes and obesity, targeted interventions addressing hyperinsulinemia and metabolic dysfunction are critical to mitigating their increased cancer risk. The association between MHT and breast cancer underscores the importance of individualised risk stratification in hormone therapy administration, particularly in women with predisposing genetic or endocrine conditions. Enhanced surveillance tailored to the unique risk profiles of endocrine disorder patients will facilitate early detection and improve clinical outcomes. However, further large-scale studies are necessary to refine these associations and develop robust, evidence-based guidelines.

Sarcomas arising in MEN1 patients: demonstrating LOH of the MEN1 locus and loss of menin expression

Multiple endocrine neoplasia type 1 (MEN1) is a hereditary tumor syndrome characterized by endocrine tumors, typically from parathyroid, pancreatic, or anterior pituitary origin. In addition, benign cutaneous soft tissue tumors are prevalent in MEN1 patients. Although sarcomas have been reported in MEN1 patients it is unclear if these tumors should be considered as part of the MEN1 syndrome. Here, five patients with a MEN1 syndrome and a sarcoma are described. In all five sarcomas loss of heterozygosity of the MEN1 gene and loss of expression of menin are shown, suggesting that sarcomas may be a phenotypic expression of MEN1 syndrome.

Menin in Cancer

The protein menin is encoded by the MEN1 gene and primarily serves as a nuclear scaffold protein, regulating gene expression through its interaction with and regulation of chromatin modifiers and transcription factors. While the scope of menin's functions continues to expand, one area of growing investigation is the role of menin in cancer. Menin is increasingly recognized for its dual function as either a tumor suppressor or a tumor promoter in a highly tumor-dependent and context-specific manner. While menin serves as a suppressor of neuroendocrine tumor growth, as seen in the cancer risk syndrome multiple endocrine neoplasia type 1 (MEN1) syndrome caused by pathogenic germline variants in MEN1, recent data demonstrate that menin also suppresses cholangiocarcinoma, pancreatic ductal adenocarcinoma, gastric adenocarcinoma, lung adenocarcinoma, and melanoma. On the other hand, menin can also serve as a tumor promoter in leukemia, colorectal cancer, ovarian and endometrial cancers, Ewing sarcoma, and gliomas. Moreover, menin can either suppress or promote tumorigenesis in the breast and prostate depending on hormone receptor status and may also have mixed roles in hepatocellular carcinoma. Here, we review the rapidly expanding literature on the role and function of menin across a broad array of different cancer types, outlining tumor-specific differences in menin's function and mechanism of action, as well as identifying its therapeutic potential and highlighting areas for future investigation.

Childhood Multiple Endocrine Neoplasia (MEN) Syndromes: Genetics, Clinical Heterogeneity and Modifying Genes

Multiple endocrine neoplasia (MEN) syndromes are part of a spectrum of clinically well-defined tumor syndromes ultimately characterized by histologically similar tumors arising in patients and families with mutations in one of the following four genes: MEN1, RET, CDKN1B, and MAX. The high level of genetic and phenotypic heterogeneity has been linked to phenocopies and modifying genes, as well as unknown mechanisms that might be investigated in the future based on preclinical and translational considerations. MEN1, also known as Wermer's syndrome (OMIM *131100), is an autosomal dominant syndrome codifying for the most frequent MEN syndrome showing high penetrance due to mutations in the MEN1 gene; nevertheless, clinical manifestations vary among patients in terms of tumor localization, age of onset, and clinical aggressiveness/severity, even within the same families. This has been linked to the effect of modifying genes, as described in the review. MEN 2-2b-4 and 5 also show remarkable clinical heterogeneity. The traditional view of genetically predisposing monogenic or multifactorial disorders is no longer valid, and mandates a change in scientific focus. Phenotypes are indeed rarely consistent across genetic backgrounds and environments. In the future, understanding factors and genetic variants that control cellular functions and the expression of disease genes should provide insights into fundamental disease processes, providing implications for counseling and therapeutic and prophylactic possibilities.

Familial states of primary hyperparathyroidism: an update

BACKGROUND

Familial primary hyperparathyroidism (PHPT) includes syndromic and non-syndromic disorders. The former are characterized by the occurrence of PHPT in association with extra-parathyroid manifestations and includes multiple endocrine neoplasia (MEN) types 1, 2, and 4 syndromes, and hyperparathyroidism-jaw tumor (HPT-JT). The latter consists of familial hypocalciuric hypercalcemia (FHH) types 1, 2 and 3, neonatal severe primary hyperparathyroidism (NSHPT), and familial isolated primary hyperparathyroidism (FIHP). The familial forms of PHPT show different levels of PHPT penetrance, developing earlier and with multiglandular involvement compared to sporadic counterpart. All these diseases exhibit Mendelian inheritance patterns, and for most of them, the genes responsible have been identified. DNA testing for predisposing mutations is helpful in index cases or in individuals with a high suspicion of the disease. Early recognition of hereditary disorders of PHPT is of great importance for the best clinical and surgical approach. Genetic testing is useful in routine clinical practice because it will also involve appropriate screening for extra-parathyroidal manifestations related to the syndrome as well as the identification of asymptomatic carriers of the mutation.

PURPOSE

The aim of the review is to discuss the current knowledge on the clinical and genetic profile of these disorders along with the importance of genetic testing in clinical practice.

Menin signaling and therapeutic targeting in breast cancer

To date, mounting evidence have shown that patients with multiple endocrine neoplasia type 1 (MEN1) may face an increased risk for breast carcinogenesis. The product of the MEN1 gene, menin, was also indicated to be an important regulator in breast cancer signaling network. Menin directly interacts with MLL, EZH2, JunD, NF-κB, PPARγ, VDR, Smad3, β-catenin and ERα to modulate gene transcriptions leading to cell proliferation inhibition. Moreover, interaction of menin-FANCD2 contributes to the enhancement of BRCA1-mediated DNA repair mechanism. Ectopic expression of menin causes Bax-, Bak- and Caspase-8-dependent apoptosis. However, despite numbers of menin inhibitors were exploited in other cancers, data on the usage of menin inhibitors in breast cancer treatment remain limited. In this review, we focused on the menin associated signaling pathways and gene transcription regulations, with the aim of elucidating its molecular mechanisms and of guiding the development of novel menin targeted drugs in breast cancer therapy.

The risk of concurrent malignancies in patients with multiple endocrine neoplasia type 1: insights into clinical characteristics of those with multiple endocrine neoplasia type 1

OBJECTIVE

Summarize and analyze the characteristics of patients with Multiple Endocrine Neoplasia type 1 (MEN-1) who were diagnosed with malignant tumors that do not belong to MEN-1 components.

METHODS

Clinical data from patients with MEN-1 who visited Peking Union Medical College Hospital between April 2012 and April 2022 were collected. We compared the clinical characteristics of patients with malignant tumors outside of their MEN-1 components to those without additional tumors. MEN-1 gene testing was performed on most of these patients using Sanger sequencing, whole-exome sequencing, or MLPA.

RESULTS

A total of 221 MEN-1 patients were diagnosed, of which 23 (10.40%) were found to have malignant tumors that did not belong to MEN-1 components, including papillary thyroid carcinoma (PTC) (4.52%), breast cancer (1.81%), urologic neoplasms (1.35%), primary hepatic carcinoma (PCC) (0.09%), meningeal sarcoma (0.05%), glioblastoma (0.05%), cervical cancer (0.05%), and lung carcinoma (0.05%). MEN-1 gene mutations were identified in 11 patients, including missense mutations, frameshift mutations, and splice mutations. The prevalence of each endocrine neoplasm, particularly gastroenteropancreatic neuroendocrine tumor, was higher in MEN-1 patients with other malignant tumors compared to MEN-1 patients without malignant tumors.

CONCLUSION

Our retrospective study revealed a higher incidence of non-MEN-1 component malignant tumors in MEN-1 patients, especially breast cancer, PTC, and urologic neoplasms. These patients also exhibit more severe clinical phenotypes of MEN-1.

A Cohort Study of CNS Tumors in Multiple Endocrine Neoplasia Type 1

PURPOSE

Multiple endocrine neoplasia type 1 (MEN1) is thought to increase the risk of meningioma and ependymoma. Thus, we aimed to describe the frequency, incidence, and specific clinical and histological features of central nervous system (CNS) tumors in the MEN1 population (except pituitary tumors).

EXPERIMENTAL DESIGN

The study population included patients harboring CNS tumors diagnosed with MEN1 syndrome after 1990 and followed up in the French MEN1 national cohort. The standardized incidence ratio (SIR) was calculated based on the French Gironde CNS Tumor Registry. Genomic analyses were performed on somatic DNA from seven CNS tumors, including meningiomas and ependymomas from patients with MEN1, and then on 50 sporadic meningiomas and ependymomas.

RESULTS

A total of 29 CNS tumors were found among the 1,498 symptomatic patients (2%; incidence = 47.4/100,000 person-years; SIR = 4.5), including 12 meningiomas (0.8%; incidence = 16.2/100,000; SIR = 2.5), 8 ependymomas (0.5%; incidence = 10.8/100,000; SIR = 17.6), 5 astrocytomas (0.3%; incidence = 6.7/100,000; SIR = 5.8), and 4 schwannomas (0.3%; incidence = 5.4/100,000; SIR = 12.7). Meningiomas in patients with MEN1 were benign, mostly meningothelial, with 11 years earlier onset compared with the sporadic population and an F/M ratio of 1/1. Spinal and cranial ependymomas were mostly classified as World Health Organization grade 2. A biallelic MEN1 inactivation was observed in 4/5 ependymomas and 1/2 meningiomas from patients with MEN1, whereas MEN1 deletion in one allele was present in 3/41 and 0/9 sporadic meningiomas and ependymomas, respectively.

CONCLUSIONS

The incidence of each CNS tumor was higher in the MEN1 population than in the French general population. Meningiomas and ependymomas should be considered part of the MEN1 syndrome, but somatic molecular data are missing to conclude for astrocytomas and schwannomas.

Risk of Malignant Neoplasm in Patients with Primary Hyperparathyroidism: A Systematic Review and Meta-analysis

This study aimed to evaluate the prevalence and risk of malignant neoplasm in primary hyperparathyroidism (PHPT) patients. Potentially eligible studies were retrieved from PubMed and Embase databases from inception to November 2023 using search strategy consisting of terms for "Primary hyperparathyroidism" and "Malignant neoplasm". Eligible study must report prevalence of malignant neoplasm among patients with PHPT or compare the risk of malignant neoplasm between patients with PHPT and comparators. Point estimates with standard errors were extracted from each study and combined using the generic inverse variance method.A total of 11,926 articles were identified. After two rounds of systematic review, 50 studies were included. The meta-analysis revealed that pooled prevalence rates of overall cancer was 0.19 (95%CI: 0.13-0.25; I2 94%). The two most prevalent types of malignancy among patients with PHPT ware papillary thyroid cancer (pooled prevalence: 0.07; 95%CI: 0.06-0.08; I2 85%) and breast cancer (pooled prevalence: 0.05; 95%CI: 0.03-0.07; I2 87%). Subgroup analysis of studies focusing on patients undergoing parathyroidectomy reported a fourfold higher prevalence of papillary thyroid cancer than the remaining studies (0.08 versus 0.02). The meta-analysis of cohort studies found a significant association between PHPT and overall cancer with the pooled risk ratio of 1.28 (95%CI: 1.23-1.33; I2 66.9%).We found that the pooled prevalence of malignant neoplasm in PHPT was 19%, with papillary thyroid cancer and breast cancer being the most prevalent types. The meta-analysis of cohort studies showed that patient with PHPT carried an approximately 28% increased risk of malignancy.

Familial multiple endocrine neoplasia type 1 with intrathoracic low-grade fibromyxoid sarcoma

BACKGROUND

Multiple endocrine neoplasia type 1 (MEN1) is a hereditary tumor syndrome characterized by endocrine tumors with mainly a parathyroid, pancreatic, or anterior pituitary origin. Low-grade fibromyxoid sarcoma (LGFMS) is a rare low-grade soft tissue tumor. There is one known report of a patient with MEN1 complicated by LGFMS, which is very rare. Our report represents the second documented case, providing valuable insights.

CASE PRESENTATION

A 31-year-old man with the chief complaint of a cough underwent chest contrast-enhanced computed tomography, which revealed a giant hypoabsorptive tumor with a maximum diameter of 23 cm in the left thoracic cavity. The patient was diagnosed with MEN1, as he also possessed a pancreatic neuroendocrine tumor and parathyroid tumor, and because his father had been found to have MEN1. To control hypercalcemia, surgery for the parathyroid tumor was initially performed, followed by surgical resection of the giant thoracic tumor for diagnosis and treatment. Histopathological examination findings of the tumor resulted in a diagnosis of LGFMS.

CONCLUSION

We experienced a very rare MEN1 with LGFMS. Although endocrine tumors generally occur more frequently in MEN1, non-endocrine tumors such as the present case should also be noted, reinforcing the importance of systemic imaging scrutiny in addition to early diagnosis and long-term follow-up of MEN1 patients.

Coincidental Occurrence of Multiple Endocrine Neoplasia Type 1 and Breast Cancer in a Young Saudi Girl: A Case Study and Genetic Analysis

Multiple Endocrine Neoplasia Type 1 (MEN-1) is an autosomal dominant familial disorder associated with tumors in both endocrine and non-endocrine organs. It is uncommon for MEN-1 to coincide with breast cancer. We present a case of a 15-year-old Saudi girl who exhibited the classic symptoms of MEN-1 and subsequently developed breast cancer. The patient's breast cancer was diagnosed using ultrasonography and core biopsy, and she was treated with surgical interventions. Despite these treatments, her cancer progressed to a metastatic stage, and her overall health deteriorated, leading to cardiopulmonary arrest at a young age. Although the simultaneous appearance of MEN-1 and breast cancer in our patient may suggest a potential link, our comprehensive genetic analysis found no relationship between her MEN-1 mutation and the onset of breast cancer. This suggests that, in this case, the two conditions co-occurred by chance. Nonetheless, additional research is needed to explore potential associations between MEN-1 and breast cancer.

Molecular and Clinical Spectrum of Primary Hyperparathyroidism

Recent data suggest an increase in the overall incidence of parathyroid disorders, with primary hyperparathyroidism (PHPT) being the most prevalent parathyroid disorder. PHPT is associated with morbidities (fractures, kidney stones, chronic kidney disease) and increased risk of death. The symptoms of PHPT can be nonspecific, potentially delaying the diagnosis. Approximately 15% of patients with PHPT have an underlying heritable form of PHPT that may be associated with extraparathyroidal manifestations, requiring active surveillance for these manifestations as seen in multiple endocrine neoplasia type 1 and 2A. Genetic testing for heritable forms should be offered to patients with multiglandular disease, recurrent PHPT, young onset PHPT (age ≤40 years), and those with a family history of parathyroid tumors. However, the underlying genetic cause for the majority of patients with heritable forms of PHPT remains unknown. Distinction between sporadic and heritable forms of PHPT is useful in surgical planning for parathyroidectomy and has implications for the family. The genes currently known to be associated with heritable forms of PHPT account for approximately half of sporadic parathyroid tumors. But the genetic cause in approximately half of the sporadic parathyroid tumors remains unknown. Furthermore, there is no systemic therapy for parathyroid carcinoma, a rare but potentially fatal cause of PHPT. Improved understanding of the molecular characteristics of parathyroid tumors will allow us to identify biomarkers for diagnosis and novel targets for therapy.

Evaluating the role of MEN1 gene expression and its clinical significance in breast cancer patients

BACKGROUND

Breast cancer is a multifactorial disease which involves number of molecular factors that are critically involved in proliferation of breast cancer cells. MEN1 gene that is traditionally known for its germline mutations in neuroendocrine tumors is associated with high risk of developing breast cancer in females with MEN1 syndrome. However, the paradoxical role of MEN1 is reported in sporadic breast cancer cases. The previous studies indicate the functional significance of MEN1 in regulating breast cells proliferation but its relevance in development and progression of breast cancer is still not known. Our study targets to find the role of MEN1 gene aberration and its clinical significance in breast cancer.

METHODS

Breast tumor and adjacent normal tissue of 142 sporadic breast cancer patients were collected at the time of surgery. The expression analysis of MEN1 mRNA and protein was done through RT-PCR, immunohistochemistry and western blotting. Further to find the genetic and epigenetic alterations, automated sequencing and MS-PCR was performed respectively. Correlation between our findings and clinical parameters was determined using appropriate statistical tests.

RESULTS

MEN1 expression was found to be significantly increased in the breast tumor tissue with its predominant nuclear localization. The elevated expression of MEN1 mRNA (63.38% cases) and protein (60.56% cases) exhibited a significant association with ER status of the patients. Most of the cases had unmethylated (53.52%) MEN1 promoter region, which can be a key factor responsible for dysregulated expression of MEN1 in breast cancer cases. Our findings also revealed the significant association of MEN1 mRNA overexpression with Age and lymph node status of the patients.

CONCLUSION

Our results indicate upregulated expression of MEN1 in sporadic breast cancer patients and it could be critically associated with development and advancement of the disease.

Cutaneous lesions and other non-endocrine manifestations of Multiple Endocrine Neoplasia type 1 syndrome

Background

Multiple Endocrine Neoplasia type 1 is a rare genetic syndrome mainly caused by mutations of MEN1 gene and characterized by a combination of several endocrine and non-endocrine manifestations. The objective of this study was to describe cutaneous lesions and other non-endocrine manifestations of MEN1 in a cohort of patients with familial (F) and sporadic (S) MEN1, compare the prevalence of these manifestations between the two cohorts, and investigate the correlation with MEN1 mutation status.

Methods

We collected phenotypic and genotypic data of 185 patients with F-MEN1 and S-MEN1 followed from 1997 to 2022. The associations between F-MEN1 and S-MEN1 or MEN1 mutation-positive and mutation-negative patients and non-endocrine manifestations were determined using chi-square or Fisher's exact tests or multivariate exact logistic regression analyses.

Results

The prevalence of angiofibromas was significantly higher in F-MEN1 than in S-MEN1 in both the whole (p < 0.001) and index case (p = 0.003) cohorts. The prevalence of lipomas was also significantly higher in F-MEN1 than in S-MEN1 (p = 0.009) and in MEN1 mutation-positive than in MEN1 mutation-negative (p = 0.01) index cases. In the whole cohort, the prevalence of lipomas was significantly higher in MEN1 mutation-positive compared to MEN1 mutation-negative patients (OR = 2.7, p = 0.02) and in F-MEN1 than in S-MEN1 (p = 0.03), only after adjustment for age. No significant differences were observed for the other non-endocrine manifestations between the two cohorts. Hibernoma and collagenoma were each present in one patient (0.5%) and meningioma and neuroblastoma in 2.7% and 0.5%, respectively. Gastric leiomyoma was present in 1.1% of the patients and uterine leiomyoma in 14% of women. Thyroid cancer, breast cancer, lung cancer, basal cell carcinoma, melanoma, and colorectal cancer were present in 4.9%, 2.7%, 1.6%, 1.6%, 2.2%, and 0.5% of the whole series, respectively.

Conclusions

We found a significantly higher prevalence of angiofibromas and lipomas in F-MEN1 compared with S-MEN1 and in MEN1 mutation-positive compared to MEN1 mutation-negative patients. In patients with one major endocrine manifestation of MEN1 , the presence of cutaneous lesions might suggest the diagnosis of MEN1 and a possible indication for genetic screening.

Neuroendocrine neoplasms in the context of inherited tumor syndromes: a reappraisal focused on targeted therapies

PURPOSE

Neuroendocrine neoplasms can occur as part of inherited disorders, usually in the form of well-differentiated, slow-growing tumors (NET). The main predisposing syndromes include: multiple endocrine neoplasias type 1 (MEN1), associated with a large spectrum of gastroenteropancreatic and thoracic NETs, and type 4 (MEN4), associated with a wide tumour spectrum similar to that of MEN1; von Hippel-Lindau syndrome (VHL), tuberous sclerosis (TSC), and neurofibromatosis 1 (NF-1), associated with pancreatic NETs. In the present review, we propose a reappraisal of the genetic basis and clinical features of gastroenteropancreatic and thoracic NETs in the setting of inherited syndromes with a special focus on molecularly targeted therapies for these lesions.

METHODS

Literature search was systematically performed through online databases, including MEDLINE (via PubMed), and Scopus using multiple keywords' combinations up to June 2022.

RESULTS

Somatostatin analogues (SSAs) remain the mainstay of systemic treatment for NETs, and radiolabelled SSAs can be used for peptide-receptor radionuclide therapy for somatostatin receptor (SSTR)-positive NETs. Apart of these SSTR-targeted therapies, other targeted agents have been approved for NETs: the mTOR inhibitor everolimus for lung, gastroenteropatic and unknown origin NET, and sunitinib, an antiangiogenic tyrosine kinase inhibitor, for pancreatic NET. Novel targeted therapies with other antiangiogenic agents and immunotherapies have been also under evaluation.

CONCLUSIONS

Major advances in the understanding of genetic and epigenetic mechanisms of NET development in the context of inherited endocrine disorders have led to the recognition of molecular targetable alterations, providing a rationale for the implementation of treatments and development of novel targeted therapies.

Clinical, pathophysiologic, genetic and therapeutic progress in Primary Bilateral Macronodular Adrenal Hyperplasia

Patients with primary bilateral macronodular adrenal hyperplasia (PBMAH) usually present bilateral benign adrenocortical macronodules at imaging and variable levels of cortisol excess. PBMAH is a rare cause of primary overt Cushing's syndrome, but may represent up to one third of bilateral adrenal incidentalomas with evidence of cortisol excess. The increased steroidogenesis in PBMAH is often regulated by various G-protein coupled receptors aberrantly expressed in PBMAH tissues; some receptor ligands are ectopically produced in PBMAH tissues creating aberrant autocrine/paracrine regulation of steroidogenesis. The bilateral nature of PBMAH and familial aggregation, led to the identification of germline heterozygous inactivating mutations of the ARMC5 gene, in 20-25% of the apparent sporadic cases and more frequently in familial cases; ARMC5 mutations/pathogenic variants can be associated with meningiomas. More recently, combined germline mutations/pathogenic variants and somatic events inactivating the KDM1A gene were specifically identified in patients affected by GIP-dependent PBMAH. Functional studies demonstrated that inactivation of KDM1A leads to GIP-receptor (GIPR) overexpression and over or down-regulation of other GPCRs. Genetic analysis is now available for early detection of family members of index cases with PBMAH carrying identified germline pathogenic variants. Detailed biochemical, imaging, and co-morbidities assessment of the nature and severity of PBMAH is essential for its management. Treatment is reserved for patients with overt or mild cortisol/aldosterone or other steroid excesses taking in account co-morbidities. It previously relied on bilateral adrenalectomy; however recent studies tend to favor unilateral adrenalectomy, or less frequently, medical treatment with cortisol synthesis inhibitors or specific blockers of aberrant GPCR.

MEN1 promotes ferroptosis by inhibiting mTOR-SCD1 axis in pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumor (pNET) is the second most common malignant tumors of the pancreas. Multiple endocrine neoplasia 1 ( MEN1) is the most frequently mutated gene in pNETs and MEN1-encoded protein, menin, is a scaffold protein that interacts with transcription factors and chromatin-modifying proteins to regulate various signaling pathways. However, the role of MEN1 in lipid metabolism has not been studied in pNETs. In this study, we perform targeted metabolomics analysis and find that MEN1 promotes the generation and oxidation of polyunsaturated fat acids (PUFAs). Meanwhile lipid peroxidation is a hallmark of ferroptosis, and we confirm that MEN1 promotes ferroptosis by inhibiting the activation of mTOR signaling which is the central hub of metabolism. We show that stearoyl-coA desaturase (SCD1) is the downstream of MEN1-mTOR signaling and oleic acid (OA), a metabolite of SCD1, recues the lipid peroxidation caused by MEN1 overexpression. The negative correlation between MEN1 and SCD1 is further verified in clinical specimens. Furthermore, we find that BON-1 and QGP-1 cells with MEN1 overexpression are more sensitive to everolimus, a widely used drug in pNETs that targets mTOR signaling. In addition, combined use everolimus with ferroptosis inducer, RSL3, possesses a more powerful ability to kill cells, which may provide a new strategy for the comprehensive therapy of pNETs.

Approach of Multiple Endocrine Neoplasia Type 1 (MEN1) Syndrome-Related Skin Tumors

Non-endocrine findings in patients with MEN1 (multiple endocrine neoplasia) syndrome also include skin lesions, especially tumor-type lesions. This is a narrative review of the English-language medical literature including original studies concerning MEN1 and dermatological issues (apart from dermatologic features of each endocrine tumor/neuroendocrine neoplasia), identified through a PubMed-based search (based on clinical relevance, with no timeline restriction or concern regarding the level of statistical significance). We identified 27 original studies involving clinical presentation of patients with MEN1 and cutaneous tumors; eight other original studies that also included the genetic background; and four additional original studies were included. The largest cohorts were from studies in Italy (N = 145 individuals), Spain (N = 90), the United States (N = 48 and N = 32), and Japan (N = 28). The age of patients varied from 18 to 76 years, with the majority of individuals in their forties. The most common cutaneous tumors are angiofibromas (AF), collagenomas (CG), and lipomas (L). Other lesions are atypical nevi, basocellular carcinoma, squamous cell carcinoma, acrochordons, papillomatosis confluens et reticularis, gingival papules, and cutaneous T-cell lymphoma of the eyelid. Non-tumor aspects are confetti-like hypopigmentation, café-au-lait macules, and gingival papules. MEN1 gene, respective menin involvement has also been found in melanomas, but the association with MEN1 remains debatable. Typically, cutaneous tumors (AF, CG, and L) are benign and are surgically treated only for cosmetic reasons. Some of them are reported as first presentation. Even though skin lesions are not pathognomonic, recognizing them plays an important role in early identification of MEN1 patients. Whether a subgroup of MEN1 subjects is prone to developing these types of cutaneous lesions and how they influence MEN1 evolution is still an open issue.

Update on the clinical management of multiple endocrine neoplasia type 1

This review provides an overview of novel insights in the clinical management of patients with Multiple Endocrine Neoplasia Type 1, focusing on the last decade since the last update of the MEN1 guidelines. With regard to Diagnosis: Mutation-negative patients with 2/3 main manifestations have a different clinical course compared to mutation-positive patients. As for primary hyperparathyroidism: subtotal parathyroidectomy is the initial procedure of choice. Current debate centres around the timing of initial parathyroidectomy as well as the controversial topic of unilateral clearance in young patients. For duodenopancreatic neuroendocrine tumours (NETs), the main challenge is accurate and individualized risk stratification to enable personalized surveillance and treatment. Thymus NETs remain one of the most aggressive MEN1-related tumours. Lung NETs are more frequent than previously thought, generally indolent, but rare aggressive cases do occur. Pituitary adenomas are most often prolactinomas and nonfunctioning microadenomas with an excellent prognosis and good response to therapy. Breast cancer is recognized as part of the MEN1 syndrome in women and periodical screening is advised. Clinically relevant manifestations are already seen at the paediatric age and initiating screening in the second decade is advisable. MEN1 has a significant impact on quality of life and US data show a significant financial burden. In conclusion, patient outcomes have improved, but much is still to be achieved. For care tailored to the needs of the individual patient and improving outcomes on an individual basis, studies are now needed to define predictors of tumour behaviour and effects of more individualized interventions.

HSP27/Menin Expression as New Prognostic Serum Biomarkers of Prostate Cancer Aggressiveness Independent of PSA

The screening of PCa is based on two tests, the total PSA test and the rectal examination. However, PSA is not specific for PCa stage confirmation, leading in false positive result and involving PCa over-diagnosis and over-treatment. HSP27 and Menin have been found to be overexpressed in a wide range of human cancers. Recent studies showed how HSP27 interacts with and stabilizes Menin to lead PCa progression and treatment resistance. The purpose of our study was to evaluate the correlation of HSP27 and Menin molecular expression, and their prognosis value in PCa with respect to clinicopathological features. Elisa was employed to measure serum HSP27 and Menin concentrations in 73 PCa patients and 80 healthy individuals. Immunohistochemistry (IHC) was used to determine HSP27 and Menin tissue expression in 57 tumors and 4 Benign Prostatic Hyperplasia (BPH) tissues. Serum HSP27 expression correlated with its tissue expression in all PCa patients, whereas serum Menin expression correlated only with tissue expression in aggressive PCa patients. Moreover, the results showed a positive correlation between HSP27 and Menin either in serum (r = 0.269; p = 0.021) or in tissue (r = 0.561; p < 0.0001). In aggressive PCa, serum expression of HSP27 and Menin was positively correlated (r = 0.664; R = 0.441; p = 0.001). The correlation between HSP27 and Menin expression in tissue was found only in patients with aggressive PCa (r = 0.606; R = 0.367; p = 0.004). Statistical analysis showed that the expression of both biomarkers was positively correlated with the hormone resistance or sensitivity, tumor aggressiveness, metastasis, Gleason Score, death and did not significantly correlate with age and PSA. Survival was illustrated by Kaplan−Meier curves; increased HSP27 and Menin expression correlated with shorter survival of PCa patients (p = 0.001 and p < 0.0001, respectively). Accuracy in predicting aggressiveness was quantified by the Area Under the Curve (AUC) of Receiver Operating Characteristic (ROC). We demonstrated that the combination of HSP27/Menin was statistically greater than PSA; it achieved an AUC of 0.824 (95% CI, 0.730−0.918; p < 0.0001). However, HSP27/Menin/PSA combination decreased the diagnostic value with an AUC of 0.569 (95% CI, 0.428−0.710; p = 0.645). Our work suggests the potential role of HSP27/Menin as diagnostic and prognostic biomarkers.

MEN1 silencing triggers the dysregulation of mTORC1 and MYC pathways in ER+ breast cancer cells

Menin, encoded by the MEN1 gene, has been identified as a critical factor regulating ESR1 transcription, playing an oncogenic role in ER+ breast cancer (BC) cells. Here, we further dissected the consequences of menin inactivation in ER+ BC cells by focusing on factors within two major pathways involved in BC, mTOR and MYC. MEN1 silencing in MCF7 and T-47D resulted in an increase in phosphor-p70S6K1, phosphor-p85S6K1 and phosphor-4EBP1 expression. The use of an AKT inhibitor inhibited the activation of S6K1 and S6RP triggered by MEN1 knockdown (KD). Moreover, MEN1 silencing in ER+ BC cells led to increased formation of the eIF4E and 4G complex. Clinical studies showed that patients with menin-low breast cancer receiving tamoxifen plus everolimus displayed a trend toward better overall survival. Importantly, MEN1 KD in MCF7 and T-47D cells led to reduced MYC expression. ChIP analysis demonstrated that menin bound not only to the MYC promoter but also to its 5' enhancer. Furthermore, E2-treated MEN1 KD MCF7 cells displayed a decrease in MYC activation, suggesting its role in estrogen-mediated MYC transcription. Finally, expression data mining in tumors revealed a correlation between the expression of MEN1 mRNA and that of several mTORC1 components and targets and a significant inverse correlation between MEN1 and two MYC inhibitory factors, MYCBP2 and MYCT1, in ER+ BC. The current work thus highlights altered mTORC1 and MYC pathways after menin inactivation in ER+ BC cells, providing insight into the crosstalk between menin, mTORC1 and MYC in ER+ BC.

Loss of MEN1 leads to renal fibrosis and decreases HGF-Adamts5 pathway activity via an epigenetic mechanism

BACKGROUND

Renal fibrosis is a serious condition that results in the development of chronic kidney diseases. The MEN1 gene is an epigenetic regulator that encodes the menin protein and its role in kidney tissue remains unclear.

METHODS

Kidney histology was examined on paraffin sections stained with hematoxylin-eosin staining. Masson's trichrome staining and Sirius red staining were used to analyze renal fibrosis. Gene and protein expression were determined by quantitative real-time PCR (qPCR) and Western blot, respectively. Immunohistochemistry staining in the kidney tissues from mice or patients was used to evaluate protein levels. Flow cytometry was used to analyze the cell cycle distributions and apoptosis. RNA-sequencing was performed for differential expression genes in the kidney tissues of the Men1f/f and Men1∆/∆ mice. Chromatin immunoprecipitation sequencing (ChIP-seq) was carried out for identification of menin- and H3K4me3-enriched regions within the whole genome in the mouse kidney tissue. ChIP-qPCR assays were performed for occupancy of menin and H3K4me3 at the gene promoter regions. Luciferase reporter assay was used to detect the promoter activity. The exacerbated unilateral ureteral obstruction (UUO) models in the Men1f/f and Men1∆/∆ mice were used to assess the pharmacological effects of rh-HGF on renal fibrosis.

RESULTS

The expression of MEN1 is reduce in kidney tissues of fibrotic mouse and human diabetic patients and treatment with fibrotic factor results in the downregulation of MEN1 expression in renal tubular epithelial cells (RTECs). Disruption of MEN1 in RTECs leads to high expression of α-SMA and Collagen 1, whereas MEN1 overexpression restrains epithelial-to-mesenchymal transition (EMT) induced by TGF-β treatment. Conditional knockout of MEN1 resulted in chronic renal fibrosis and UUO-induced tubulointerstitial fibrosis (TIF), which is associated with an increased induction of EMT, G2/M arrest and JNK signaling. Mechanistically, menin recruits and increases H3K4me3 at the promoter regions of hepatocyte growth factor (HGF) and a disintegrin and metalloproteinase with thrombospondin motifs 5 (Adamts5) genes and enhances their transcriptional activation. In the UUO mice model, exogenous HGF restored the expression of Adamts5 and ameliorated renal fibrosis induced by Men1 deficiency.

CONCLUSIONS

These findings demonstrate that MEN1 is an essential antifibrotic factor in renal fibrogenesis and could be a potential target for antifibrotic therapy.

Multiple endocrine neoplasia type 1 or 4: detection of hyperfunctioning parathyroid glands with 18F-fluorocholine PET/CT. Illustrative cases and pitfalls

¹⁸F-fluorocholine (FCH) PET/CT is now well established to detect the hyperfunctioning parathyroid glands (HFPTG) in a case of sporadic primary hyperparathyroidism (pHPT), but only limited evidence is available about the utility of FCH PET/CT to detect the HFPTG in patients with multiple endocrine neoplasia (MEN) type 1 or 4. The pHPT in this context frequently consists in a multiglandular disease with small hyperplastic glands rather than adenomas, which is challenging for imaging modalities. The data of patients with MEN1 or MEN4 after parathyroidectomy referred to FCH PET/CT for presurgical localization of HFPTG were retrospectively reviewed, including follow-up after parathyroidectomy, in search for diagnostic performance and for potential pitfalls. In the present cohort, 16 patients referred to FCH PET/CT as part of their initial pHPT work-up were subsequently operated, 44 abnormal parathyroid glands (PT) were resected, of which 32 (73%) had been detected on FCH PET/CT and 2 considered as equivocal foci. Nine patients referred to FCH PET/CT for recurrent pHPT who were subsequently operated, 14 abnormal PT were resected, all had been detected on FCH PET/CT. FCH PET/CT permitted a unilateral approach for PTx in 4 of them. In one patient with MEN4 and pHPT, the HFPTG could not be visualized on FCH PET/CT but was localized by ultrasonography. Several causes of false positive or false negative results, incidental finding and pitfalls are listed and discussed. FCH PET/CT has a positive benefit/risk ratio in the detection of HFPTG in case of MEN1 (the data in MEN4 being currently very limited) with the most effective detection rate of current imaging modalities for HFPTG, few pitfalls, and an adequate impact on patient management compared to sesta MIBI SPECT and ultrasonography.

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.

The Research Landscape of Multiple Endocrine Neoplasia Type 1 (2000–2021): A Bibliometric Analysis

Introduction

This study aimed to investigate the landscape of Multiple Endocrine Neoplasia Type 1 research during the last 22 years using machine learning and text analysis.

Method

In December 2021, all publications indexed under the MeSH term “Multiple Endocrine Neoplasia Type 1” were obtained from PubMed. The whole set of search results was downloaded in XML format, and metadata such as title, abstract, keywords, mesh words, and year of publication were extracted from the original XML files for bibliometric evaluation. The Latent Dirichlet allocation (LDA) topic modeling method was used to analyze specific themes.

Results

This study eventually contained 1,407 publications. Among them, there are 768 (54.58%) case reports and reviews. Text analysis based on MeSH words revealed that the most often studied clinical areas include therapy efficacy, prognosis, and genetic diagnosis. The majority of basic study is focused on genetic alterations. The LDA topic model further identifies three topic clusters include basic research, treatment cluster, and diagnosis cluster. In the basic research cluster, many studies are focused on the expression of Menin. The primary focus of the therapy cluster is pancreatic resections and parathyroidectomy. In the diagnose cluster, the main focus is on Genetic Diagnosis and screening strategies for Hereditary Cancer Syndrome.

Conclusion

The current state of research on MEN1 is far from adequate. Research on rare diseases MEN1 necessitates implementing a broad research program involving multiple centers to advance MEN1 research together.

The Importance of Periodical Screening for Primary Hyperparathyroidism in a Pituitary Tumor Cohort in Searching Patients with MEN1 and its Genetic Profile

OBJECTIVE

Multiple endocrine neoplasia type 1 (MEN1) is a rare genetic syndrome characterized by parathyroid, anterior pituitary, and/or duodenopancreatic neuroendocrine tumors. Studies have indicated that investigating primary hyperparathyroidism (pHPT) with subsequent genetic screening may be an essential tool for the early diagnosis of MEN1 in patients with pituitary tumors (PTs). This study aimed to investigate the presence of pHPT in patients with PTs and, subsequently, to screen for genetic mutations and related tumors in those with MEN1 Syndrome.

METHODS

This study included 255 patients with PTs who were assessed for the presence of MEN1 from serum calcium and parathyroid hormone measurements. Mutation screening of the MEN1, CDKN1B, and AIP genes was performed in the index cases showing the MEN1 phenotype.

RESULTS

Five PT-evaluated patients presented a clinical condition compatible with MEN1. These patients had a younger age of onset and a more severe clinical condition. Genetic analysis identified a frameshift mutation in the MEN1 gene in one of the cases with the MEN1 phenotype, but point mutations in CDKN1B and AIP were not detected in any of these patients.

CONCLUSION

Our findings show that periodic screening for pHPT in patients with PTs may be useful to detect MEN1 syndrome; thus, it is recommended in those patients genetic analysis of MEN1 gene and an additional search of related tumors. By contrast, our results suggest that CDKN1B and AIP mutations do not seem to play a relevant role in the pathogenesis of MEN1.

Overview of the 2022 WHO Classification of Familial Endocrine Tumor Syndromes

This review of the familial tumor syndromes involving the endocrine organs is focused on discussing the main updates on the upcoming fifth edition of the WHO Classification of Endocrine and Neuroendocrine Tumors. This review emphasizes updates on histopathological and molecular genetics aspects of the most important syndromes involving the endocrine organs. We describe the newly defined Familial Cancer Syndromes as MAFA-related, MEN4, and MEN5 as well as the newly reported pathological findings in DICER1 syndrome. We also describe the updates done at the new WHO on the syndromic and non-syndromic familial thyroid diseases. We emphasize the problem of diagnostic criteria, mention the new genes that are possibly involved in this group, and at the same time, touching upon the role of some immunohistochemical studies that could support the diagnosis of some of these conditions. As pathologists play an important role in identifying tumors within a familial cancer syndrome, we highlight the most important clues for raising the suspicious of a syndrome. Finally, we highlight the challenges in defining these entities as well as determining their clinical outcome in comparison with sporadic tumors. Instead of the usual subject review, we present the highlights of the updates on familial cancer syndromes by answering select questions relevant to practicing pathologists.

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.

A MEN1 Patient Presenting With Multiple Parathyroid Adenomas and Transient Hypercortisolism: A Case Report and Literature Review

BACKGROUND

Multiple endocrine neoplasia type 1 (MEN1) is a hereditary endocrine syndrome caused by mutations in MEN1 tumor suppressor gene.

CASE PRESENTATION

A 53-year-old Chinese female was admitted to Division of Endocrinology, Tongji Hospital, for hypercalcemic crisis. Increased level of parathyroid hormone (PTH) was confirmed by laboratory tests, and imaging examination showed multiple parathyroid adenomas. Based on gene analysis, the patient was diagnosed as MEN1 associated hyperparathyroidism (HPT) by gene analysis with c.1378C>T (p.Arg460Ter) mutation in MEN1 gene. Her condition was complicated by transient hypercortisolism, mammary mass and uterine leiomyoma. After subtotal parathyroidectomy, PTH and serum calcium levels returned to normal.

CONCLUSION

HPT with multiple parathyroid adenomas is an indication of MEN1 gene mutation. Serum cortisol and its circadian rhythm can be abnormal in the presence of hypercalcemia and high PTH. These parameters can return to normal after parathyroidectomy.

Genomic and Transcriptomic Analyses of Breast Cancer Primaries and Matched Metastases in AURORA, the Breast International Group (BIG) Molecular Screening Initiative

AURORA aims to study the processes of relapse in metastatic breast cancer (MBC) by performing multi-omics profiling on paired primary tumors and early-course metastases. Among 381 patients (primary tumor and metastasis pairs: 252 targeted gene sequencing, 152 RNA sequencing, 67 single nucleotide polymorphism arrays), we found a driver role for GATA1 and MEN1 somatic mutations. Metastases were enriched in ESR1, PTEN, CDH1, PIK3CA, and RB1 mutations; MDM4 and MYC amplifications; and ARID1A deletions. An increase in clonality was observed in driver genes such as ERBB2 and RB1. Intrinsic subtype switching occurred in 36% of cases. Luminal A/B to HER2-enriched switching was associated with TP53 and/or PIK3CA mutations. Metastases had lower immune score and increased immune-permissive cells. High tumor mutational burden correlated to shorter time to relapse in HR+/HER2- cancers. ESCAT tier I/II alterations were detected in 51% of patients and matched therapy was used in 7%. Integration of multi-omics analyses in clinical practice could affect treatment strategies in MBC. SIGNIFICANCE: The AURORA program, through the genomic and transcriptomic analyses of matched primary and metastatic samples from 381 patients with breast cancer, coupled with prospectively collected clinical data, identified genomic alterations enriched in metastases and prognostic biomarkers. ESCAT tier I/II alterations were detected in more than half of the patients.This article is highlighted in the In This Issue feature, p. 2659.

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 1: a broad overview

This review article discusses the diagnoses and treatment of patients with multiple endocrine neoplasia type 1 (MEN 1). The most common tumors associated with MEN 1 are located in the pancreas, pituitary, and parathyroid glands. Less common tumors include neuroendocrine tumors of the lung and thymus, adrenal tumors, and cutaneous lesions. This article describes the diagnosis, clinical manifestations, treatment, and surveillance of tumors associated with patients who are diagnosed with MEN 1.

Well-Differentiated Bronchopulmonary Neuroendocrine Tumors: More Than One Entity

INTRODUCTION

Until now, well-differentiated bronchopulmonary neuroendocrine tumors (bpNET) occurring either sporadically (sp-bpNET) or in the context of multiple endocrine neoplasia type 1 (MEN1) and diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) are regarded as similar entities. However, in contrast to sp-bpNET: MEN1-related and DIPNECH-related bpNET rarely metastasize or lead to bpNET-related death. We aimed to describe and compare the course of the disease of sp-bpNET, DIPNECH- and MEN1-related bpNET.

METHODS

All patients with histologically confirmed MEN1-related bpNET from the DutchMEN Study Group database (1990-2017), patients with resected sp-bpNET and DIPNECH patients referred to a Dutch European Neuroendocrine Tumor Society center between 2000 and 2018 were included. Fisher's exact test was used for comparison between groups. The primary end point was disease-specific mortality (DSM). Kaplan-Meier and logrank test were used to compare survival. Cox regression was used to identify risk factors for DSM in the sp-bpNET subgroup.

RESULTS

We included 112 sp-bpNET, 29 MEN1, and 27 DIPNECH patients. Tumor classification was similar across subgroups. A total of 20 patients (18%) with sp-bpNET died because of bpNET, compared with none in the MEN1 group and DIPNECH group. Median disease-specific survival was 12.3 (confidence interval: 6.3-18.3) years for patients with sp-bpNET, and not estimable for the other subgroups (p < 0.001). Differences in baseline characteristics did not explain worse survival in sp-bpNET. Tumor classification and age at diagnosis were independent risk factors for DSM in sp-bpNET.

CONCLUSIONS

Patients with sp-bpNET have a significantly higher DSM compared with MEN1 or DIPNECH-related bpNET, unexplained by differences in baseline characteristics. This implies that not all bpNET are similar entities.

Antisense Oligonucleotide-Based Therapeutic against Menin for Triple-Negative Breast Cancer Treatment

The tumor suppressor menin has dual functions, acting either as a tumor suppressor or as an oncogene/oncoprotein, depending on the oncological context. Triple-negative breast cancer (TNBC) is characterized by the lack of expression of the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (ERBB2/HER2) and is often a basal-like breast cancer. TNBC is associated with a dismal prognosis and an insufficient response to chemotherapies. Previously, menin was shown to play a proliferative role in ER-positive breast cancer; however, the functions of menin in TNBC remain unknown. Here, we have demonstrated that menin is expressed in various TNBC subtypes with the strongest expression in the TNBC Hs 578T cells. The depletion of menin by an antisense oligonucleotide (ASO) inhibits cell proliferation, enhances apoptosis in Hs 578T cells, highlighting the oncogenic functions of menin in this TNBC model. ASO-based menin silencing also delays the tumor progression of TNBC xenografts. Analysis of the menin interactome suggests that menin could drive TNBC tumorigenesis through the regulation of MLL/KMT2A-driven transcriptional activity, mRNA 3′-end processing and apoptosis. The study provides a rationale behind the use of ASO-based therapy, targeting menin in monotherapy or in combination with chemo or PARP inhibitors for menin-positive TNBC treatments.

A Direct Comparison of Patients With Hereditary and Sporadic Pancreatic Neuroendocrine Tumors: Evaluation of Clinical Course, Prognostic Factors and Genotype-Phenotype Correlations

Introduction

Pancreatic neuroendocrine tumors (PNETs) in hereditary syndromes pose a significant challenge to clinicians. The rarity of these syndromes and PNETs itself make it difficult to directly compare them with sporadic PNETs. Despite research suggesting differences between these two entities, the same approach is used in hereditary and sporadic PNETs.

Methods

We included 63 patients with hereditary PNET (GpNET) and 145 with sporadic PNET (SpNET) in a retrospective observational study. Clinical and genetic data were collected in two Polish endocrine departments from January 2004 to February 2020. Only patients with confirmed germline mutations were included in the GpNET cohort. We attempted to establish prognostic factors of metastases and overall survival in both groups and genotype-phenotype correlations in the GpNET group.

Results

Patients with GpNET were younger and diagnosed earlier, whereas their tumors were smaller and more frequently multifocal compared with patients with SpNET. Metastases occurred more frequently in the SpNET group, and their appearance was associated with tumor size in both groups. GpNET patients had longer overall survival (OS). OS was affected by age, age at diagnosis, sex, grade, stage, tumor diameter, occurrence and localization of metastases, type of treatment, and comorbidities. In the MEN1 group, carriers of frameshift with STOP codon, splice site, and missense mutations tended to have less advanced disease, while patients with mutations in exon 2 tended to have metastases more frequently.

Conclusions

Direct comparisons of GpNET and SpNET demonstrate significant differences in the clinical courses of both entities, which should force different approaches. A larger group of patients with GpNET should be assessed to confirm genotype-phenotype correlations.

A Box of Chemistry to Inhibit the MEN1 Tumor Suppressor Gene Promoting Leukemia

Targeting protein-protein interactions (PPIs) with small-molecule inhibitors has become a hotbed of modern drug development. In this review, we describe a new class of PPI inhibitors that block menin from binding to MLL proteins. Menin is encoded by the MEN1 tumor suppressor, but acts as an essential cofactor for MLL/KMT2A-rearranged leukemias. The most promising menin-MLL inhibitors belong to the thienopyrimidine class and have recently entered phase I/II clinical trials for treating acute leukemias characterized by MLL/KMT2A translocations or NPM1 mutations. As single agents, thienopyrimidine compounds eradicate leukemia in a xenograft models of primary leukemic cells belonging to the MLL-rearranged or NPM1-mutant subtypes. These compounds are well tolerated with few or no side effects, which is remarkable given the tumor-suppressor function of menin. The menin-MLL inhibitors highlight how leukemia patients could benefit from a targeted epigenetic therapy with novel PPI inhibitors obtained by directed chemical evolution.

New therapies for patients with multiple endocrine neoplasia type 1

In 1953, for the first time, Paul Wermer described a family presenting endocrine gland neoplasms over several generations. The transmission was autosomal dominant and the penetrance was high. Forty years later in 1997, the multiple endocrine neoplasia type 1 (MEN1) gene was sequenced, thus enabling diagnosis and early optimal treatment. Patients carrying the MEN1 gene present endocrine but also non-endocrine tumors. Parathyroid, pancreatic and pituitary impairment are the three main types of endocrine involvement. The present article details therapeutic management of hyperparathyroidism, neuroendocrine pancreatic tumors and pituitary adenomas in patients carrying the MEN1 gene. Significant therapeutic progress has in fact been made in the last few years. As concerns the parathyroid glands, screening of family members and regular monitoring of affected subjects now raise the question of early management of parathyroid lesions and optimal timing of parathyroid surgery. As concerns the duodenum-pancreas, proton-pump inhibitors are able to control gastrin-secreting syndrome, reducing mortality in MEN1 patients. Mortality in MEN1 patients is no longer mainly secondary to uncontrolled hormonal secretion but to metastatic (mainly pancreatic) disease progression. Tumor risk requires regular monitoring of morphological assessment, leading to iterative pancreatic surgery in a large number of patients. Finally, pituitary adenomas in MEN1 patients are traditionally described as aggressive, invasive and resistant to medical treatment. However, regular pituitary screening showed them to be in fact infra-centimetric and non-secreting in the majority of patients. Consequently, it is necessary to regularly monitor MEN1 patients, with regular clinical, biological and morphological work-up. Several studies showed that this regular monitoring impairs quality of life. Building a relationship of trust between patients and care provider is therefore essential. It enables the patient to be referred for psychological or psychiatric care in difficult times, providing long-term support and preventing any breakdown in continuity of care.

Clinical aspects of multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type 1 (MEN1) is a rare syndrome characterized by the co-occurrence of primary hyperparathyroidism, duodenopancreatic neuroendocrine tumours (NETs) and/or pituitary adenomas. MEN1 can predispose patients to other endocrine and non-endocrine tumours, such as cutaneous tumours, central nervous system tumours and breast cancer. Endocrine tumours in patients with MEN1 differ from sporadic tumours in that they have a younger age at onset, present as multiple tumours in the same organ and have a different clinical course. Therefore, patients with overt MEN1 and those who carry a MEN1 mutation should be offered tailored biochemical and imaging screening to detect tumours and evaluate their progression over time. Fortunately, over the past 10 years, knowledge about the clinical phenotype of these tumours has markedly progressed, thanks to the implementation of national registries, particularly in France and the Netherlands. This Review provides an update on the clinical management of MEN1-related tumours. Epidemiology, the clinical picture, diagnostic work-up and the main lines of treatment for MEN1-related tumours are summarized. Controversial therapeutic aspects and issues that still need to be addressed are also discussed. Moreover, special attention is given to MEN1 manifestations in children and adolescents.

Multiple Endocrine Neoplasia Type 1: Latest Insights

Multiple endocrine neoplasia type 1 (MEN1), a rare tumor syndrome that is inherited in an autosomal dominant pattern, is continuing to raise great interest for endocrinology, gastroenterology, surgery, radiology, genetics, and molecular biology specialists. There have been 2 major clinical practice guidance papers published in the past 2 decades, with the most recent published 8 years ago. Since then, several new insights on the basic biology and clinical features of MEN1 have appeared in the literature, and those data are discussed in this review. The genetic and molecular interactions of the MEN1-encoded protein menin with transcription factors and chromatin-modifying proteins in cell signaling pathways mediated by transforming growth factor β/bone morphogenetic protein, a few nuclear receptors, Wnt/β-catenin, and Hedgehog, and preclinical studies in mouse models have facilitated the understanding of the pathogenesis of MEN1-associated tumors and potential pharmacological interventions. The advancements in genetic diagnosis have offered a chance to recognize MEN1-related conditions in germline MEN1 mutation-negative patients. There is rapidly accumulating knowledge about clinical presentation in children, adolescents, and pregnancy that is translatable into the management of these very fragile patients. The discoveries about the genetic and molecular signatures of sporadic neuroendocrine tumors support the development of clinical trials with novel targeted therapies, along with advancements in diagnostic tools and surgical approaches. Finally, quality of life studies in patients affected by MEN1 and related conditions represent an effort necessary to develop a pharmacoeconomic interpretation of the problem. Because advances are being made both broadly and in focused areas, this timely review presents and discusses those studies collectively.

The Management of Neuroendocrine Tumors of the Lung in MEN1: Results From the Dutch MEN1 Study Group

INTRODUCTION

Multiple endocrine neoplasia type 1 (MEN1)-related neuroendocrine tumors (NETs) of the lung are mostly indolent, with a good prognosis. Nevertheless, cases of aggressive lung NET do occur, and therefore the management of individual patients is challenging.

AIM

To assess tumor growth and the survival of patients with MEN1-related lung NETs at long-term follow-up.

METHODS

The population-based Dutch MEN1 Study Group database (n = 446) was used to identify lung NETs by histopathological and radiological examinations. Tumor diameter was assessed. Linear mixed models and the Kaplan-Meier method were used for analyzing tumor growth and survival. Molecular analyses were performed on a lung NET showing particularly aggressive behavior.

RESULTS

In 102 patients (22.9% of the total MEN1 cohort), 164 lesions suspected of lung NETs were identified and followed for a median of 6.6 years. Tumor diameter increased 6.0% per year. The overall 15-year survival rate was 78.0% (95% confidence interval: 64.6-94.2%) without lung NET-related death. No prognostic factors for tumor growth or survival could be identified. A somatic c.3127A > G (p.Met1043Val) PIK3CA driver mutation was found in a case of rapid growing lung NET after 6 years of indolent disease, presumably explaining the sudden change in course.

CONCLUSION

MEN1-related lung NETs are slow growing and have a good prognosis. No accurate risk factors for tumor growth could be identified. Lung NET screening should therefore be based on well-informed, shared decision-making, balancing between the low absolute risk of an aggressive tumor in individuals and the potential harms of frequent thoracic imaging.

Health-Related Quality of Life in Patients with Multiple Endocrine Neoplasia Type 1

INTRODUCTION

Multiple endocrine neoplasia type 1 (MEN1) is a hereditary endocrine tumor syndrome characterized by the triad of primary hyperparathyroidism, duodenopancreatic neuroendocrine tumors (pNETs), and pituitary tumors. Patients are confronted with substantial morbidity and are consequently at risk for an impaired quality of life (QOL). Meticulous assessment of QOL and associated factors in a representative population is needed to understand the full spectrum of the burden of the disease.

PATIENTS AND METHODS

A cross-sectional study was performed using the national Dutch MEN1 cohort. Patients with a confirmed MEN1 mutation received the SF-36 Health Related Quality of Life questionnaire and questions regarding sociodemographic and medical history.

RESULTS

A total of 227 of 285 (80%) eligible MEN1 patients returned the questionnaires. Health-related QOL scores (HRQOL) in MEN1 patients were significantly lower for the majority of subscales of the SF-36 in comparison with the general Dutch population. The most consistent predictor for HRQOL was employment status, followed by the presence of a pituitary tumor. 16% of patients harboring a pNET and 29% of patients with a pituitary tumor according to the medical records, reported that they were unaware of such a tumor. These subgroups of patients had several significant better QOL scores than patients who were aware of their pNET or pituitary tumors.

CONCLUSION

Patients with MEN1 have an impaired QOL in comparison with the general Dutch population warranting special attention within routine care. For daily practice, physicians should be aware of their patients' impaired QOL and of the impact of unemployment on QOL.

Incidental finding of MEN-1 syndrome during staging and follow-up of breast carcinoma

Type 1 multiple endocrine neoplasia (MEN-1) syndrome is an autosomal dominant disease, associated with germline mutations in the MEN-1 tumour suppressor gene (encoding the menin protein). Recent studies, through a better characterisation of the functions of the menin protein, have started to demonstrate how changes in this protein may be related to breast cancer. We present the case of a patient whose diagnosis of MEN-1 syndrome was made during treatment for a breast tumour-this diagnosis was obtained after finding multiple neoplastic lesions that fitted the MEN-1 syndrome spectrum, during the initial staging and subsequent follow-up of a breast tumour. In line with the growing evidence that links MEN-1 syndrome to breast cancer tumorigenesis, this case report highlights the following question: should we start screening this subset of patients earlier for breast cancer?

Men1 disruption in Nkx3.1-deficient mice results in ARlow/CD44+ microinvasive carcinoma development with the dysregulated AR pathway

Dysregulated androgen receptor (AR) plays a crucial role in prostate cancer (PCa) development, though further factors involved in its regulation remain to be identified. Recently, paradoxical results were reported on the implication of the MEN1 gene in PCa. To dissect its role in prostate luminal cells, we generated a mouse model with inducible Men1 disruption in Nkx3.1-deficient mice in which mouse prostatic intraepithelial neoplasia (mPIN) occur. Prostate glands from mutant and control mice were analyzed pathologically and molecularly; cellular and molecular analyses were carried out in PCa cell lines after MEN1 knockdown (KD) by siRNA. Double-mutant mice developed accelerated mPIN and later displayed microinvasive adenocarcinoma. Markedly, early-stage lesions exhibited a decreased expression of AR and its target genes, accompanied by reduced CK18 and E-cadherin expression, suggesting a shift from a luminal to a dedifferentiated epithelial phenotype. Intriguingly, over 60% of menin-deficient cells expressed CD44 at a later stage. Furthermore, MEN1 KD led to the increase in CD44 expression in PC3 cells re-expressing AR. Menin bound to the proximal AR promoter and regulated AR transcription via the H3K4me3 histone mark. Interestingly, the cell proliferation of AR-dependent cells (LNCaP, 22Rv1, and VCaP), but not of AR-independent cells (DU145, PC3), responded strongly to MEN1 silencing. Finally, menin expression was found reduced in some human PCa. These findings highlight the regulation of the AR promoter by menin and the crosstalk between menin and the AR pathway. Our data could be useful for better understanding the increasingly reported AR-negative/NE-negative subtype of PCa and the mechanisms underlying its development.

Multiple Endocrine Neoplasia Type 1 (MEN1) Phenocopy Due to a Cell Cycle Division 73 (CDC73) Variant

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by the combined occurrence of parathyroid tumors, pituitary adenomas, and pancreatic neuroendocrine neoplasms (PNENs). MEN1 is caused by germline MEN1 mutations in > 75% of patients, and the remaining 25% of patients may have mutations in unidentified genes or represent phenocopies with mutations in genes such as cell cycle division 73 (CDC73), the calcium sensing receptor (CASR), and cyclin-dependent kinase inhibitor 1B (CDKN1B), which are associated with the hyperparathyroidism-jaw tumor syndrome, familial hypocalciuric hypercalcemia type 1, and MEN4, respectively. Here, we report a heterozygous c.1138C>T (p.Leu380Phe) CDC73 germline variant in a clinically diagnosed MEN1 patient, based on combined occurrence of primary hyperparathyroidism, acromegaly, and a PNEN. Characterization of the PNEN confirmed it was a neuroendocrine neoplasm as it immuno-stained positively for chromogranin and glucagon. The rare variant p.Leu380Phe occurred in a highly conserved residue, and further analysis using RNA-Scope indicated that it was associated with a significant reduction in CDC73 expression in the PNEN. Previously, CDC73 mutations have been reported to be associated with tumors of the parathyroids, kidneys, uterus, and exocrine pancreas. Thus, our report of a patient with PNEN and somatotrophinoma who had a CDC73 variant, provides further evidence that CDC73 variants may result in a MEN1 phenocopy.

Involvement of the MEN1 Gene in Hormone-Related Cancers: Clues from Molecular Studies, Mouse Models, and Patient Investigations

MEN1 mutation predisposes patients to multiple endocrine neoplasia type 1 (MEN1), a genetic syndrome associated with the predominant co-occurrence of endocrine tumors. Intriguingly, recent evidence has suggested that MEN1 could also be involved in the development of breast and prostate cancers, two major hormone-related cancers. The first clues as to its possible role arose from the identification of the physical and functional interactions between the menin protein, encoded by MEN1, and estrogen receptor α and androgen receptor. In parallel, our team observed that aged heterozygous Men1 mutant mice developed cancerous lesions in mammary glands of female and in the prostate of male mutant mice at low frequencies, in addition to endocrine tumors. Finally, observations made both in MEN1 patients and in sporadic breast and prostate cancers further confirmed the role played by menin in these two cancers. In this review, we present the currently available data concerning the complex and multifaceted involvement of MEN1 in these two types of hormone-dependent cancers.

Menin and Menin-Associated Proteins Coregulate Cancer Energy Metabolism

The interplay between glycolysis and mitochondrial oxidative phosphorylation (OXPHOS) is central to maintain energy homeostasis. It remains to be determined whether there is a mechanism governing metabolic fluxes based on substrate availability in microenvironments. Here we show that menin is a key transcription factor regulating the expression of OXPHOS and glycolytic genes in cancer cells and primary tumors with poor prognosis. A group of menin-associated proteins (MAPs), including KMT2A, MED12, WAPL, and GATA3, is found to restrain menin's full function in this transcription regulation. shRNA knockdowns of menin and MAPs result in reduced ATP production with proportional alterations of cellular energy generated through glycolysis and OXPHOS. When shRNA knockdown cells are exposed to metabolic stress, the dual functionality can clearly be distinguished among these metabolic regulators. A MAP can negatively counteract the regulatory mode of menin for OXPHOS while the same protein positively influences glycolysis. A close-proximity interaction between menin and MAPs allows transcriptional regulation for metabolic adjustment. This coordinate regulation by menin and MAPs is necessary for cells to rapidly adapt to fluctuating microenvironments and to maintain essential metabolic functions.