Genetics of Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine neoplasms (pNENs): Genetic and environmental biomarkers for risk of occurrence and prognosis

Pancreatic neuroendocrine neoplasms (pNENs) are rare and heterogeneous tumors arising from neuroendocrine cells, representing approximately 10 % of all Gastro-Entero-Pancreatic neuroendocrine neoplasms. While most pNENs are sporadic, a subset is associated with genetic syndromes such as multiple endocrine neoplasia type 1 (MEN1) or von Hippel-Lindau disease (VHL). pNENs are further classified into functioning and non-functioning tumors, with distinct clinical behaviors, prognoses, and treatment approaches. This review explores genetic and environmental biomarkers that influence the risk, prognosis, and therapeutic responses in pNENs. The epidemiology of pNENs reveals an increasing incidence, primarily due to advancements in imaging techniques. Genetic factors play a pivotal role, with germline mutations in MEN1, VHL, and other genes contributing to familial pNENs. Somatic mutations, including alterations in the mTOR pathway and DNA maintenance genes such as DAXX and ATRX, are critical in sporadic pNENs. These mutations, along with epigenetic dysregulation and transcriptomic alterations, underpin the diverse clinical and molecular phenotypes of pNENs. Emerging evidence suggests that epigenetic changes, including DNA methylation profiles, can stratify pNEN subtypes and predict disease progression. Environmental and lifestyle factors, such as diabetes, smoking, and chronic pancreatitis, have been linked to an increased risk of sporadic pNENs. While the association between these factors and tumor progression is still under investigation, their potential role in influencing therapeutic outcomes warrants further study. Advances in systemic therapies, including somatostatin analogs, mTOR inhibitors, and tyrosine kinase inhibitors, have improved disease management. Biomarkers such as Ki-67, somatostatin receptor expression, and O6-methylguanine-DNA methyltransferase (MGMT) status are being evaluated for their predictive value. Novel approaches, including the use of circulating biomarkers (NETest, circulating tumor cells, and ctDNA) and polygenic risk scores, offer promising avenues for non-invasive diagnosis and monitoring. Despite these advancements, challenges remain, including the need for large, well-annotated datasets and validated biomarkers. Future research should integrate multi-omics approaches and leverage liquid biopsy technologies to refine diagnostic, prognostic, and therapeutic strategies. Interdisciplinary collaborations and global consortia are crucial for overcoming current limitations and translating research findings into clinical practice. These insights hold promise for improving prevention, early detection, and tailored treatments, ultimately enhancing patient outcomes.

Pancreatic Neuroendocrine Tumor: The Case Report of a Patient with Germline FANCD2 Mutation and Tumor Analysis Using Single-Cell RNA Sequencing

Background: Neuroendocrine neoplasms are a rare and heterogeneous group of neoplasms. Small-sized (≤2 cm) pancreatic neuroendocrine tumors (PanNETs) are of particular interest as they are often associated with aggressive behavior, with no specific prognostic or progression markers.

METHODS

This article describes a clinical case characterized by a progressive growth of nonfunctional PanNET requiring surgical treatment in a patient with a germline FANCD2 mutation, previously not reported in PanNETs. The patient underwent whole exome sequencing and single-cell RNA sequencing.

RESULTS

The patient underwent surgical treatment. We confirmed the presence of the germline mutation FANCD2 and also detected the germline mutation WNT10A. The cellular composition of the PanNET was analyzed using single-cell sequencing, and the main cell clusters were identified. We analyzed the tumor genomics, and used the data to define the effect the germline FANCD2 mutation had.

CONCLUSIONS

Analysis of the mutational status of patients with PanNET may provide additional data that may influence treatment tactics, refine the plan for monitoring such patients, and provide more information about the pathogenesis of PanNET. PanNET research using scRNA-seq data may help in predicting the effect of therapy on neuroendocrine cells with FANCD2 mutations.

Germline Testing Identifies Pathogenic/Likely Pathogenic Variants in Patients with Pancreatic Neuroendocrine Tumors

Ten percent of pancreatic neuroendocrine tumors (pNET) are related to inherited syndromes (MEN1, MEN4, VHL, NF1, and TSC). Growing evidence suggests that clinically sporadic pNETs can also harbor germline pathogenic variants. In this study, we report the prevalence of pathologic/likely pathologic (P/LP) germline variants in a high-risk cohort and an unselected cohort. We collected clinical data of patients with pNETs seen at MD Anderson Cancer Center and Johns Hopkins Hospital. The high-risk cohort included (n = 132) patients seen at MD Anderson Cancer Center who underwent germline testing for high-risk criteria (early onset, personal or family history of cancer, and syndromic features) between 2013 and 2019. The unselected cohort included (n = 106) patients seen at Johns Hopkins Hospital who underwent germline testing following their diagnosis of pNETs between 2020 and 2022. In the high-risk cohort (n = 132), 33% (n = 44) had P/LP variants. The majority of the patients had P/LP variants in MEN1 56% (n = 25), followed by DNA repair pathways 18% (n = 8), and 7% (n = 3) in MSH2 (Lynch syndrome). Patients with P/LP were younger (45 vs. 50 years; P = 0.002). In the unselected cohort (n = 106), 21% (n = 22) had P/LP. The majority were noted in DNA repair pathways 40% (n = 9) and MEN1 36% (n = 8). Multifocal tumors correlated with the presence of P/LP (P = 0.0035). MEN1 germline P/LP variants correlated with younger age (40 vs. 56 years; P = 0.0012), presence of multifocal tumors (P < 0.0001), and World Health Organization grade 1 histology (P = 0.0078). P/LP variants are prevalent in patients with clinically sporadic pNET irrespective of high-risk features. The findings support upfront universal germline testing in all patients with pNET. Prevention Relevance: Here, we present germline data from the largest reported cohort of patients with pNET (n = 238), comprising both a high-risk cohort and an unselected cohort. In both cohorts, we identify a high number of P/LPs, including those in the DNA repair pathway. Our findings support universal germline testing in patients with pNET.

Turning Points in Cross-Disciplinary Perspective of Primary Hyperparathyroidism and Pancreas Involvements: Hypercalcemia-Induced Pancreatitis, MEN1 Gene-Related Tumors, and Insulin Resistance

We aimed to provide an in-depth analysis with respect to three turning points in pancreas involvement in primary hyperparathyroidism (PHP): hypercalcemia-induced pancreatitis (HCa-P), MEN1 (multiple endocrine neoplasia)-related neuroendocrine tumors (NETs), and insulin resistance (IR). This was a comprehensive review conducted via a PubMed search between January 2020 and January 2024. HCa-P (n = 9 studies, N = 1375) involved as a starting point parathyroid NETs (n = 7) or pancreatitis (n = 2, N = 167). Case report-focused analysis (N = 27) showed five cases of pregnancy PHP-HCa-P and three reports of parathyroid carcinoma (female/male ratio of 2/1, ages of 34 in women, men of 56). MEN1-NET studies (n = 7) included MEN1-related insulinomas (n = 2) or MEN1-associated PHP (n = 2) or analyses of genetic profile (n = 3), for a total of 877 MEN1 subjects. In MEN1 insulinomas (N = 77), the rate of associated PHP was 78%. Recurrence after parathyroidectomy (N = 585 with PHP) was higher after less-than-subtotal versus subtotal parathyroidectomy (68% versus 45%, p < 0.001); re-do surgery was 26% depending on surgery for pancreatic NETs (found in 82% of PHP patients). MEN1 pathogenic variants in exon 10 represented an independent risk factor for PHP recurrence. A single pediatric study in MEN1 (N = 80) revealed the following: a PHP rate of 80% and pancreatic NET rate of 35% and 35 underlying germline MEN1 pathogenic variants (and 3/35 of them were newly detected). The co-occurrence of genetic anomalies included the following: CDC73 gene variant, glucokinase regulatory protein gene pathogenic variant (c.151C>T, p.Arg51*), and CAH-X syndrome. IR/metabolic feature-focused analysis identified (n = 10, N = 1010) a heterogeneous spectrum: approximately one-third of adults might have had prediabetes, almost half displayed some level of IR as reflected by HOMA-IR > 2.6, and serum calcium was positively correlated with HOMA-IR. Vitamin D deficiency was associated with a higher rate of metabolic syndrome (n = 1). Normocalcemic and mildly symptomatic hyperparathyroidism (n = 6, N = 193) was associated with a higher fasting glucose and some improvement after parathyroidectomy. This multilayer pancreas/parathyroid analysis highlighted a complex panel of connections from pathogenic factors, including biochemical, molecular, genetic, and metabolic factors, to a clinical multidisciplinary panel.

Pancreatic Neuroendocrine Tumors: Signaling Pathways and Epigenetic Regulation

Pancreatic neuroendocrine tumors (PNETs) are characterized by dysregulated signaling pathways that are crucial for tumor formation and progression. The efficacy of traditional therapies is limited, particularly in the treatment of PNETs at an advanced stage. Epigenetic alterations profoundly impact the activity of signaling pathways in cancer development, offering potential opportunities for drug development. There is currently a lack of extensive research on epigenetic regulation in PNETs. To fill this gap, we first summarize major signaling events that are involved in PNET development. Then, we discuss the epigenetic regulation of these signaling pathways in the context of both PNETs and commonly occurring-and therefore more extensively studied-malignancies. Finally, we will offer a perspective on the future research direction of the PNET epigenome and its potential applications in patient care.