Multiple endocrine neoplasia type 4 (MEN4): a thorough update on the latest and least known men syndrome.

PURPOSE: Multiple endocrine neoplasia type 4 (MEN4) is a rare multiglandular endocrine neoplasia syndrome, associated with a wide tumor spectrum but hallmarked by primary hyperparathyroidism, which represents the most common clinical feature, followed by pituitary (functional and non-functional) adenomas, and neuroendocrine tumors. MEN4 clinically overlaps MEN type 1 (MEN1) but differs from it for milder clinical features and an older patient's age at onset. The underlying mutated gene, CDKN1B, encodes the cell cycle regulator p27, implicated in cellular proliferation, motility and apoptosis. Given the paucity of MEN4 cases described in the literature, possible genotype-phenotype correlations have not been thoroughly assessed, and specific clinical recommendations are lacking. The present review provides an extensive overview of molecular genetics and clinical features of MEN4, with the aim of contributing to delineate peculiar strategies for clinical management, screening and follow-up of the last and least known MEN syndrome. METHODS: A literature search was performed through online databases like MEDLINE and Scopus. CONCLUSIONS: MEN4 is much less common that MEN1, tend to present later in life with a more indolent course, although involving the same primary organs as MEN1. As a consequence, MEN4 patients might need specific diagnostic and therapeutic approaches and a different strategy for screening and follow-up. Further studies are needed to assess the real oncological risk of MEN4 carriers, and to establish a standardized screening protocol. Furthermore, a deeper understanding of molecular genetics of MEN4 is needed in order to explore p27 as a novel therapeutic target.

Vitamin D deficiency and tumor aggressiveness in gastroenteropancreatic neuroendocrine tumors.

PURPOSE: Data regarding vitamin D status in patients affected by gastroenteropancreatic (GEP) neuroendocrine tumor (NET) are limited and often showing contrasting results. The aim of the study was to evaluate the incidence of vitamin D deficiency (<20 ng/mL) in GEP-NET patients and compare the 25-hydroxyvitamin D (25(OH)D) levels with clinicopathological parameters and clinical outcome. METHODS: A retrospective cross-sectional study including 75 low grade (G1-G2) GEP-NETs and 123 healthy controls matched for age, sex, and body mass index, was performed. RESULTS: GEP-NET patients had significantly lower 25(OH)D levels compared to controls (17.9 ± 7.8 vs 24.2 ± 7.7 ng/mL, p < 0.0001). Ileal NETs were associated to lower 25(OH)D levels compared to other primary tumor sites (p = 0.049) and small bowel resection posed a significant increased risk of severe vitamin D deficiency (OR = 2.81, 95% CI = 1.25-3.37, p = 0.018). No correlation with somatostatin analogs treatment was found. 25(OH)D levels were significantly lower in G2 compared to G1 GEP-NETs (15.6 ± 7.8 vs 19.9 ± 7.4 ng/mL, p = 0.016) and in patients with progressive disease (12.6 ± 5.7 ng/mL) compared to those with stable disease (mean 21.5 ± 8.2 ng/mL, p = 0.001) or tumor free after surgery (19.6 ± 7.3 ng/mL, p = 0.002). Patients with vitamin D deficiency and insufficiency had shorter progression-free survival compared to those with sufficiency (p = 0.014), whereas no correlation was found with disease-specific survival. CONCLUSIONS: Vitamin D deficiency is highly prevalent among GEP-NETs and could be associated with high tumor grade and disease progression. Therefore, the monitoring of 25(OH)D levels is relevant in these patients and vitamin D supplementation should be considered in the management of GEP-NET patients with vitamin D deficiency or insufficiency.

From microbiota toward gastro-enteropancreatic neuroendocrine neoplasms: Are we on the highway to hell?

Gut microbiota is represented by different microorganisms that colonize the intestinal tract, mostly the large intestine, such as bacteria, fungi, archaea and viruses. The gut microbial balance has a key role in several functions. It modulates the host's metabolism, maintains the gut barrier integrity, participates in the xenobiotics and drug metabolism, and acts as protection against gastro-intestinal pathogens through the host's immune system modulation. The impaired gut microbiota, called dysbiosis, may be the result of an imbalance in this equilibrium and is linked with different diseases, including cancer. While most of the studies have focused on the association between microbiota and gastrointestinal adenocarcinomas, very little is known about gastroenteropancreatic (GEP) neuroendocrine neoplasms (NENs). In this review, we provide an overview concerning the complex interplay between gut microbiota and GEP NENs, focusing on the potential role in tumorigenesis and progression in these tumors.

Quality of Life in Patients with Neuroendocrine Neoplasms: The Role of Severity, Clinical Heterogeneity, and Resilience.

CONTEXT: Although health-related quality of life (HRQoL) is a fundamental outcome in oncological clinical trials, its evaluation in the neuroendocrine neoplasm (NEN) research field is still limited. OBJECTIVES: This study assessed the role of clinical severity (ie, presence or absence of metastasis and lines of therapies) and heterogeneity (ie, primary site, types of therapy, biology, and surgery) of NEN in relation to HRQoL, as well as resilience as a moderator between clinical severity and HRQoL. DESIGN: Cross-sectional multicentric study. SETTING: Italian university hospitals. PATIENTS: A total of 99 Italian patients (53 men and 46 women) with NEN and ranged in age from 22-79 years old. MAIN OUTCOME MEASURE: Severity and heterogeneity of NENs, HRQoL, and resilience. RESULTS: The presence of metastasis and a greater number of therapies affected the global health and some physical symptoms. Resilience was associated with global health, functional status, and some physical symptoms, and it moderated the impact of metastases on constipation and of the multiple therapies on diarrhea and financial problems. Patients with NEN in districts other than the gastroenteropancreatic system and those in follow-up perceived fewer physical symptoms than their counterparts. Patients with a sporadic NEN perceived their functional status, global health, and disease-related worries as better than those with a hereditary NEN. Patients who underwent surgery were lower in constipation than their counterparts. CONCLUSION: These findings highlight the need to assess the relationships between the clinical severity and heterogeneity of NEN with HRQoL and the role of resilience in improving patients' HRQoL.

Advances in the Management of Medullary Thyroid Carcinoma: Focus on Peptide Receptor Radionuclide Therapy.

Effective treatment options in advanced/progressive/metastatic medullary thyroid carcinoma (MTC) are currently limited. As in other neuroendocrine neoplasms (NENs), peptide receptor radionuclide therapy (PRRT) has been used as a therapeutic option in MTC. To date, however, there are no published reviews dealing with PRRT approaches. We performed an in-depth narrative review on the studies published in this field and collected information on registered clinical trials related to this topic. We identified 19 published studies, collectively involving more than 200 patients with MTC, and four registered clinical trials. Most cases of MTC were treated with PRRT with somatostatin analogues (SSAs) radiolabelled with 90 yttrium (90Y) and 177 lutetium (177Lu). These radiopharmaceuticals show efficacy in the treatment of patients with MTC, with a favourable radiological response (stable disease, partial response or complete response) in more than 60% of cases, coupled with low toxicity. As MTC specifically also expresses cholecystokinin receptors (CCK2Rs), PRRT with this target has also been tried, and some randomised trials are ongoing. Overall, PRRT seems to have an effective role and might be considered in the therapeutic strategy of advanced/progressive/metastatic MTC.

Emerging Therapies in Pheochromocytoma and Paraganglioma: Immune Checkpoint Inhibitors in the Starting Blocks.

Pheochromocytoma and paraganglioma are neuroendocrine neoplasms, originating in the adrenal medulla and in parasympathetic and sympathetic autonomic nervous system ganglia, respectively. They usually present as localized tumours curable with surgery. However, these tumours may exhibit heterogeneous clinical course, ranging from no/minimal progression to aggressive (progressive/metastatic) behavior. For this setting of patients, current therapies are unsatisfactory. Immune checkpoint inhibitors have shown outstanding results for several types of solid cancers. We therefore aimed to summarize and discuss available data on efficacy and safety of current FDA-approved immune checkpoint inhibitors in patients with pheochromocytoma and paraganglioma. After an extensive search, we found 15 useful data sources (four full-published articles, four supplements of scientific journals, seven ongoing registered clinical trials). The data we detected, even with the limit of the small number of patients treated, make a great expectation on the therapeutic use of immune checkpoint inhibitors. Besides, the newly detected predictors of response will (hopefully) be of great helps in selecting the subset of patients that might benefit the most from this class of drugs. Finally, new trials are in the starting blocks, and they are expected to shed in the next future new light on a therapy, which is considered a milestone in oncology.

Lanreotide Therapy vs Active Surveillance in MEN1-Related Pancreatic Neuroendocrine Tumors < 2 Centimeters.

PURPOSE: Pancreatic neuroendocrine tumors (pNETs) are frequent in multiple endocrine neoplasia type 1 (MEN1) syndrome. They are usually not surgically treated unless larger than 1 to 2 cm or a growth rate > 0.5 cm per year. Somatostatin analogues represent one of the main therapeutic options in pNETs, but they have never been prospectively investigated in MEN1-related pNETs. The aim of this study was to prospectively evaluate the effectiveness of lanreotide in patients with MEN1-related pNETs < 2 cm. METHODS: MEN1 patients with 1 or more pNETs < 2 cm of maximal diameter were considered. Study design was prospective observational, comparing patients treated with lanreotide autogel 120 mg every 28 days (LAN group) and patients in active surveillance, not receiving any therapy (AS group). RESULTS: Forty-two patients were enrolled: 23 in LAN and 19 in AS group. Median follow-up was 73 months. Initial imaging identified a total of 91 pNETs. The median progression-free survival was significantly longer in the LAN than in the AS group (median not reached vs 40 months, P < 0.001). In the LAN group, 4 patients had an objective tumor response, 15 patients had stable disease, while 4 had tumor progression. In the AS group, 13 patients had pNET progression, while 6 were stable. CONCLUSIONS: This is the first prospective study evaluating the efficacy of somatostatin analogues in MEN1-related pNETs. These findings highlight that lanreotide autogel is effective as antiproliferative therapy in MEN1-related pNETs < 2cm, suggesting the utility of somatostatin analogues to arrest the development of tumor lesions as well as to delay or avoid pancreatic surgery.

A rare rarity: Neuroendocrine tumor of the esophagus.

Esophageal Neuroendocrine tumors (NETs) are rare, aggressive and lacking specific symptoms. This causes a diagnostic delay, worsening the prognosis. Numerous cases are reported in literature, without a consensus on the management. Our aim was to clarify epidemiology, clinical presentation, diagnostic, therapeutic management of esophageal NETs. Extensive literature search identified a total of 226 articles. One hundred twenty-five articles (n = 1676) met the inclusion criteria, showing that: the incidence of esophageal NET varies geographically; men (60-70 years) are more affected; smoking and alcohol abuse are the major risk factors; dysphagia, weight loss, appetite loss are the most common clinical features. The histotypes include high-grade small and large cell esophageal carcinomas and low-grade carcinoid tumors. Mixed neuroendocrine/non-neuroendocrine neoplasms are the most common. Often the diagnosis occurs randomly on endoscopic examination. Circulating markers, functional combined with conventional imaging contributes to the diagnosis and management. Treatment depends on type, grade and stage of the tumor.

Immune checkpoint blockade for Merkel cell carcinoma: actual findings and unanswered questions.

PURPOSE: Merkel cell carcinoma (MCC) is a rare, aggressive neuroendocrine carcinoma arising from the skin. We aimed to review and deal with some of the most relevant controversial topics on the correct use of immunotherapy for the treatment of MCC. METHODS: The primary search was carried out via PubMed, EMBASE, and the Cochrane Library (until 31st May, 2018), while other articles and guidelines were retrieved from related papers or those referenced in these papers. Additionally, we performed an extensive search on ClinicalTrials.gov to gather information on the ongoing clinical trials related to this specific topic. RESULTS: We performed an up-to-date critical review taking into account the results of both retrospective and prospective published studies evaluating these issues: Are there any predictive criteria of response to immunotherapy? What is the correct place of immunotherapy in the treatment algorithm of MCC? What is the best choice after immunotherapy failure? What to do with patients for whom immunotherapy is not been feasible or contraindicated? How long should immunotherapy be prolonged, and what follow-up should be offered after complete response? CONCLUSION: The therapeutic landscape of MCC is rapidly evolving: many open issues will probably be resolved, and many other questions are likely to arise in the next few years. The results of ongoing prospective clinical trials and of several other studies on these issues are eagerly awaited.

On and off-target effects of telomere uncapping G-quadruplex selective ligands based on pentacyclic acridinium salts.

Quadruplexes DNA are present in telomeric DNA as well as in several cancer-related gene promoters and hence affect gene expression and subsequent biological processes. The conformations of G4 provide selective recognition sites for small molecules and thus these structures have become important drug-design targets for cancer treatment. The DNA G-quadruplex binding pentacyclic acridinium salt RHPS4 (1) has many pharmacological attributes of an ideal telomere-targeting agent but has undesirable off-target liabilities. Notably a cardiovascular effect was evident in a guinea pig model, manifested by a marked and sustained increase in QTcB interval. In accordance with this, significant interaction with the human recombinant ß2 adrenergic receptor, and M1, M2 and M3 muscarinic receptors was observed, together with a high inhibition of the hERG tail current tested in a patch clamp assay. Two related pentacyclic structures, the acetylamines (2) and (3), both show a modest interaction with ß2 adrenergic receptor, and do not significatively inhibit the hERG tail current while demonstrating potent telomere on-target properties comparing closely with 1. Of the two isomers, the 2-acetyl-aminopentacycle (2) more closely mimics the overall biological profile of 1 and this information will be used to guide further synthetic efforts to identify novel variants of this chemotype, to maximize on-target and minimize off-target activities. Consequently, the improvement of toxicological profile of these compounds could therefore lead to the obtainment of suitable molecules for clinical development offering new pharmacological strategies in cancer treatment.

Evaluation of the in vitro and in vivo antiangiogenic effects of denosumab and zoledronic acid.

Denosumab (Dmab) and zoledronic acid (ZOL) are antiresorptive agents, with different mechanisms of action, that are indicated for delaying the onset of skeletal-related events in patients with bone metastases from solid tumors. Clinical and preclinical data suggest that ZOL may have also anti-angiogenic activity; however, the effects of Dmab (a fully humanized antibody against the receptor activator of nuclear factor kappa B ligand) on angiogenesis are largely unknown. The objective of this study was to compare the potential anti-angiogenic activity of Dmab with that of ZOL in preclinical models. Dmab (0.31 to 160 µM) had no effect on the viability of human MDA-MB-436 and CG5 breast cancer cells or human umbilical vein endothelial cells (HUVECs) and no effect on tubule formation or invasion of HUVECs. In contrast, ZOL (0.31 to 160 µM) decreased the viability of breast cancer and HUVECs in a time- and concentration-dependent manner and also inhibited HUVEC tubule formation and invasion. In vivo, ZOL (20 µg/mouse for three times a week for three consecutive weeks) inhibited angiogenesis in Matrigel plugs and inhibited the growth and neo-angiogenesis of CG5 xenografts in athymic nude mice. In contrast, Dmab (10 mg/Kg twice a week for 4 consecutive weeks) had no effect on Matrigel vascularization or xenograft growth in this model. These findings support the potential antiangiogenic and anticancer activity of ZOL in vitro and in vivo and further suggest that Dmab does not have antiangiogenic activity. Additional studies are needed to elucidate the potential anticancer activity of Dmab.