Dyslipidemia, lipid-lowering agents and neuroendocrine neoplasms: new horizons

Metabolic changes in neuroendocrine neoplasms

Neuroendocrine neoplasms (NENs) are a group of highly heterogeneous neoplasms originating from neuroendocrine cells with a gradually increased incidence. Metabolic change is one of the recognized markers of tumor progression, which has been extensively and systematically studied in other malignant tumors. However, metabolic change in NENs has been relatively poorly studied, and systematic reviews are lacking. We reviewed the relationship between metabolic changes and NENs from the aspects of glucose metabolism, lipid metabolism, metabolic syndrome, amino acid metabolism and metabolomics, and discussed the potential therapeutic strategies of metabolic changes for NENs.

Mendelian Randomization Assessment of the Genetic Effects of Lipid-Lowering Drugs on Digestive System Cancers

The relationship between lipid-lowering drugs and the risk of digestive system cancers remains unclear. This study aims to assess the risk association between lipid-lowering drugs and digestive system cancers through mendelian randomization (MR) analysis. We utilized genetic instruments to substitute for the exposure to lipid-lowering drugs, including expression quantitative trait loci (eQTL) for HMGCR, PCSK9, and NPC1L1, as well as genetic variants associated with low-density lipoprotein (LDL) from the Global Lipids Genetics Consortium's genome-wide association study (GWAS) data for target genes. We used MR and SMR methods to assess the risk estimates of lipid-lowering drug target genes on digestive system tumors. The MR analysis indicated a negative association between HMGCR-mediated LDL and hepatocellular carcinoma (OR = 0.06, 95% CI: 0.00-0.81, p = 0.03), and a positive association between NPC1L1-mediated LDL and gastric cancer risk (OR = 15.45, 95% CI: 5.96-40.56, p < 0.01). In the SMR analysis, it was observed that HMGCR expression decreased the risk of hepatocellular carcinoma (OR = 0.11, 95% CI: 0.02-0.68, p = 0.02), while NPC1L1 expression increased the risk of gastric cancer (OR = 1.33, 95% CI: 1.08-1.64, p < 0.01). Our study results suggested a potential risk association between HMGCR inhibitors and NPC1L1 with hepatocellular carcinoma and gastric cancer.

Functioning neuroendocrine tumors (NET): Minimum requirements for a NET specialist

INTRODUCTION AND AIMS

Functioning neuroendocrine tumors (f-NETs) represent a minority of all NETs, however their management is challenging due to the impact on patients' survival and quality of life. In addition to f-NETs, paraneoplastic syndromes (PNS) are due to substances that are not related to the primary anatomical site, they can develop in different phases of NETs evolution, and might complicate the patient's clinical course. Dedicated guidelines are still scanty. We aim to review available literature on f-NETs to propose a useful tool for clinicians in order to improve the diagnostic process and the management.

METHODS

Narrative review focused on f-NETs.

RESULTS

The most common f-NETs include insulinomas, gastrinomas and carcinoid syndrome (CS)- associated NETs. Symptoms related to hormone production may overlap with other common endocrine and gastrointestinal disorders, highlighting the pivotal role of multidisciplinary management. Somatostatin analogs (SSAs) represent the gold standard first-line treatment of most f-NETs, often followed by or combined with other treatments (surgery, liver-directed therapies, targeted therapies, peptide receptor radionuclide therapy). Paraneoplastic syndromes can develop in different phases of NET evolution and might complicate the patient's clinical course and response to therapy.

CONCLUSIONS

The management of hormonal syndromes is challenging and must be based on the multidisciplinary approach. Herein, we pointed out the minimal requirements for a NET specialist in the diagnosis and treatment of f-NETs. Efforts should be made to improve the awareness of functioning forms, to understand their pathogenesis and to improve their management.

The association between non-HDL cholesterol and high-grade pancreatic neuroendocrine neoplasms

PURPOSE

High-density lipoprotein cholesterol (HDL-c) plays an important role in tumorigenesis in several endocrine-related cancers. Few studies have shown the effect of non-HDL-c in malignant tumors. The present study aimed to identify the association between non-HDL-c and high-grade pancreatic neuroendocrine neoplasms (PNENs).

METHODS

A total of 197 PNEN patients who underwent surgery were analyzed retrospectively. Clinical and histopathological features, such as patients' age and sex, tumor location and size, tumor grade, the level of serum total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c) and fasting plasma-glucose levels were obtained. Non-HDL-c was calculated as total cholesterol - HDL-c. The relationships between those features and high-grade PNENs were identified using logistic regression analysis.

RESULTS

Among the 197 patients with PNENs, a lower HDL-c level was more common seen in patients with poorly differentiated PNENs than in those with well-differentiated PNENs (P < 0.05). The non-HDL-c/HDL-c ratio was greater in patients with poorly differentiated PNENs than in those with well-differentiated PNENs (P < 0.01). Similarly, a greater proportion of patients with a non-HDL-c/HDL-c ratio larger than 5 was found in patients with poorly differentiated PNENs than in those with well-differentiation PNENs (P < 0.01). Multivariate logistic analysis showed that the non-HDL-c/HDL-c ratio was positively associated with poorly differentiated PNENs (odds ratio (OR) = 1.45, 95% conference interval (CI):1.13-1.87). Similarly, the risk of poorly differentiated PNENs increased significantly in patients with a non-HDL-c/HDL-c greater than 5 (OR = 14.13, 95%CI: 2.98-66.89). The risk of high-grade PNENs increased in patients with a high non-HDL-c/HDL-c ratio (OR = 1.27, 95% CI: 1.04-1.55), and the risk also increased markedly when the ratio was greater than 5 (OR = 5.00, 95%CI: 1.28-19.49).

CONCLUSIONS

A high ratio of non-HDL-c/HDL-c was associated with high-grade PNENs or poorly differentiated PNENs.

Neuroendocrine Tumors and Survival Rates in Multiple Endocrine Neoplasia Type 1 Patients: Impact of Gender Difference

INTRODUCTION

Multiple endocrine neoplasia type 1 (MEN-1) is the most common inherited syndrome associated with NET development and gender-specific differences are emerging in neuroendocrine tumors (NETs). This study aimed to analyze gender difference in a single cohort of MEN-1 patients focusing on duodeno-pancreatic (DP)-NET and survival rates.

METHODS

MEN-1 patients referred to the Endocrinology Unit of the "Federico II" University of Naples, ENETS CoE, were retrospectively evaluated.

RESULTS

Among 100 MEN-1 patients enrolled, 59 (59%) were female and 41 (41%) male, and mean age at diagnosis was 39.4 years (range 5-86). No statistically significant association was identified between MEN-1 clinical manifestations and gender (primary hyperparathyroidism [PHPT] p: 1.0, DP-NET p: 0.83, pituitary adenoma [PA] p: 0.84, lung NET p: 0.64, and thymic NET p: 0.10), and similarly, age at diagnosis of MEN-1 and its individual manifestations was similar between genders. Survival analysis revealed no statistically significant difference between genders in DP-NET patients regarding progression disease p: 1.0 and death p: 1.0. Mean progression-free survival (PFS) of patients with DP-NET was 98.6 months (range 3-288), and mean overall survival (OS) was 130.1 months (range 3-444 months), without differences between genders (PFS p: 0.67 and OS p: 0.60). The Kaplan-Meier survival curves for PFS and OS showed no differences between genders (PFS p: 0.92; OS p: 0.87).

CONCLUSION

In this MEN-1 cohort, no gender differences in the occurrence of PHPT, PA, DP-NET, lung NET, and thymic NET, nor in survival outcomes including PFS and OS within the DP-NET subcohort, emerged. Therefore, this study supports similar screening and follow-up for both male and female MEN-1 patients.

Investigating the causal relationship between gut microbiota and gastroenteropancreatic neuroendocrine neoplasms: a bidirectional Mendelian randomization study

Background

The interaction between the intestinal flora and gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) remains poorly understood, despite the known effect of the gut microbiota on gastrointestinal adenocarcinomas. Hence, the present research aimed to determine the potential causal correlation between the intestinal flora and GEP-NENs by conducting a bidirectional Mendelian randomization (MR) analysis.

Methods

Two-sample MR analysis was conducted using the summary statistics of the gut microbiota from the MiBioGen consortium and those of GEP-NENs from the FinnGen research project. The inverse-variance weighted approach was utilized as the primary analytical method. To enhance the robustness of our findings, multiple sensitivity tests were performed, including Cochran's Q test for evaluating heterogeneity, the MR-Egger intercept test to detect horizontal pleiotropy, and the MR-PRESSO test to identify outliers and assess pleiotropy bias. Additionally, a leave-one-out analysis was performed to validate the consistency of our findings. The MR-Steiger test was also utilized to determine the causal direction in the correlation between the gut microbiota and GEP-NENs. Finally, a reverse MR analysis was performed to assess reverse causality between the intestinal flora and GEP-NENs.

Results

We identified 42 taxa of the gut microbiota that were potentially causally associated with GEP-NENs; of these taxa, 7, 8, 11, and 16 taxa were causally associated with pancreatic NENs, colorectal NENs, small intestinal NENs, and gastric NENs, respectively. After adjusting for false discovery rate (FDR) correction, we found significant causal links of Euryarchaeota with small intestinal NENs and Family XIII UCG-001 with gastric NENs. The sensitivity analyses confirmed the stability of these correlations. In the reverse MR analysis, colorectal NENs and small intestinal NENs were found to be associated with variations in 8 and 6 different taxa of the gut microbiota, respectively. After adjusting for FDR correction, no significant causal links were detected between GEP-NENs and the intestinal flora.

Conclusion

The present study reveals a potential causal association between certain taxa of the intestinal flora and GEP-NENs, thus providing new perspectives regarding the role of the intestinal flora in the development of these tumors. These insights could provide innovative approaches to screen and prevent these diseases.