The Integrated Stress Response in Pancreatic Development, Tissue Homeostasis, and Cancer.

Present in all eukaryotic cells, the integrated stress response (ISR) is a highly coordinated signaling network that controls cellular behavior, metabolism, and survival in response to diverse stresses. The ISR is initiated when any 1 of 4 stress-sensing kinases (protein kinase R-like endoplasmic reticulum kinase [PERK], general control non-derepressible 2 [GCN2], double-stranded RNA-dependent protein kinase [PKR], heme-regulated eukaryotic translation initiation factor 2α kinase [HRI]) becomes activated to phosphorylate the protein translation initiation factor eukaryotic translation initiation factor 2α (eIF2α), shifting gene expression toward a comprehensive rewiring of cellular machinery to promote adaptation. Although the ISR has been shown to play an important role in the homeostasis of multiple tissues, evidence suggests that it is particularly crucial for the development and ongoing health of the pancreas. Among the most synthetically dynamic tissues in the body, the exocrine and endocrine pancreas relies heavily on the ISR to rapidly adjust cell function to meet the metabolic demands of the organism. The hardwiring of the ISR into normal pancreatic functions and adaptation to stress may explain why it is a commonly used pro-oncogenic and therapy-resistance mechanism in pancreatic ductal adenocarcinoma and pancreatic neuroendocrine tumors. Here, we review what is known about the key roles that the ISR plays in the development, homeostasis, and neoplasia of the pancreas.

A novel model for predicting postoperative liver metastasis in R0 resected pancreatic neuroendocrine tumors: integrating computational pathology and deep learning-radiomics.

BACKGROUND: Postoperative liver metastasis significantly impacts the prognosis of pancreatic neuroendocrine tumor (panNET) patients after R0 resection. Combining computational pathology and deep learning radiomics can enhance the detection of postoperative liver metastasis in panNET patients. METHODS: Clinical data, pathology slides, and radiographic images were collected from 163 panNET patients post-R0 resection at Fudan University Shanghai Cancer Center (FUSCC) and FUSCC Pathology Consultation Center. Digital image analysis and deep learning identified liver metastasis-related features in Ki67-stained whole slide images (WSIs) and enhanced CT scans to create a nomogram. The model's performance was validated in both internal and external test cohorts. RESULTS: Multivariate logistic regression identified nerve infiltration as an independent risk factor for liver metastasis (p < 0.05). The Pathomics score, which was based on a hotspot and the heterogeneous distribution of Ki67 staining, showed improved predictive accuracy for liver metastasis (AUC = 0.799). The deep learning-radiomics (DLR) score achieved an AUC of 0.875. The integrated nomogram, which combines clinical, pathological, and imaging features, demonstrated outstanding performance, with an AUC of 0.985 in the training cohort and 0.961 in the validation cohort. High-risk group had a median recurrence-free survival of 28.5 months compared to 34.7 months for the low-risk group, showing significant correlation with prognosis (p < 0.05). CONCLUSION: A new predictive model that integrates computational pathologic scores and deep learning-radiomics can better predict postoperative liver metastasis in panNET patients, aiding clinicians in developing personalized treatments.

The Value of Textbook Outcome in Benchmarking Pancreatoduodenectomy for Nonfunctioning Pancreatic Neuroendocrine Tumors.

BACKGROUND: Textbook outcome (TO) is a composite variable that can define the quality of pancreatic surgery. The aim of this study is to evaluate TO after pancreatoduodenectomy (PD) for nonfunctioning pancreatic neuroendocrine tumors (NF-PanNETs). PATIENTS AND METHODS: All patients who underwent PD for NF-PanNETs (2007-2016) in different centers were included in this retrospective study. TO was defined as the absence of severe postoperative complications and mortality, length of hospital stay ≤ 19 days, R0 resection, and at least 12 lymph nodes harvested. RESULTS: Overall, 477 patients were included. The TO rate was 32%. Tumor size [odds ratio (OR) 1.696; p = 0.013], a minimally invasive approach (OR 12.896; p = 0.001), and surgical volume (OR 2.062; p = 0.023) were independent predictors of TO. The annual frequency of PDs increased over time as well as the overall rate of TO. At a median follow-up of 44 months, patients who achieved TO had similar disease-free (p = 0.487) and overall survival (p = 0.433) rates compared with patients who did not achieve TO. TO rate in patients with NF-PanNET > 2 cm was 35% versus 27% in patients with NF-PanNET ≤ 2 cm (p = 0.044). Considering only NF-PanNETs > 2 cm, patients with TO and those without TO had comparable 5-year overall survival rates (p = 0.766) CONCLUSIONS: TO is achieved in one-third of patients after PD for NF-PanNETs and is not associated with a benefit in terms of long-term survival.

Multiregion WES of metastatic pancreatic neuroendocrine tumors revealed heterogeneity in genomic alterations, immune microenvironment and evolutionary patterns.

Pancreatic neuroendocrine tumors (PanNETs), though uncommon, have a high likelihood of spreading to other body parts. Previously, the genetic diversity and evolutionary patterns in metastatic PanNETs were not well understood. To investigate this, we performed multiregion sampling whole-exome sequencing (MRS-WES) on samples from 10 patients who had not received prior treatment for metastatic PanNETs. This included 29 primary tumor samples, 31 lymph node metastases, and 15 liver metastases. We used the MSK-MET dataset for survival analysis and validation of our findings. Our research indicates that mutations in the MEN1/DAXX genes might trigger the early stages of PanNET development. We categorized the patients based on the presence (MEN1/DAXXmut, n = 7) or absence (MEN1/DAXXwild, n = 3) of these mutations. Notable differences were observed between the two groups in terms of genetic alterations and clinically relevant mutations, confirmed using the MSK-MET dataset. Notably, patients with mutations in MEN1/DAXX/ATRX genes had a significantly longer median overall survival compared to those without these mutations (median not reached vs. 43.63 months, p = 0.047). Multiplex immunohistochemistry (mIHC) analysis showed a more prominent immunosuppressive environment in metastatic tumors, especially in patients with MEN1/DAXX mutations. These findings imply that MEN1/DAXX mutations lead PanNETs through a unique evolutionary path. The disease's progression pattern indicates that PanNETs can spread early, even before clinical detection, highlighting the importance of identifying biomarkers related to metastasis to guide personalized treatment strategies.

A radiomics-based interpretable model to predict the pathological grade of pancreatic neuroendocrine tumors.

OBJECTIVES: To develop a computed tomography (CT) radiomics-based interpretable machine learning (ML) model to predict the pathological grade of pancreatic neuroendocrine tumors (pNETs) in a non-invasive manner. METHODS: Patients with pNETs who underwent contrast-enhanced abdominal CT between 2010 and 2022 were included in this retrospective study. Radiomics features were extracted, and five radiomics-based ML models, namely logistic regression (LR), random forest (RF), support vector machine (SVM), XGBoost, and GaussianNB, were developed. The performance of these models was evaluated using a time-independent testing set, and metrics such as sensitivity, specificity, accuracy, and the area under the receiver operating characteristic curve (AUC) were calculated. The accuracy of the radiomics model was compared to that of needle biopsy. The Shapley Additive Explanation (SHAP) tool and the correlation between radiomics and biological features were employed to explore the interpretability of the model. RESULTS: A total of 122 patients (mean age: 50 ± 14 years; 53 male) were included in the training set, whereas 100 patients (mean age: 48 ± 13 years; 50 male) were included in the testing set. The AUCs for LR, SVM, RF, XGBoost, and GaussianNB were 0.758, 0.742, 0.779, 0.744, and 0.745, respectively, with corresponding accuracies of 73.0%, 70.0%, 77.0%, 71.9%, and 72.9%. The SHAP tool identified two features of the venous phase as the most significant, which showed significant differences among the Ki-67 index or mitotic count subgroups (p < 0.001). CONCLUSIONS: An interpretable radiomics-based RF model can effectively differentiate between G1 and G2/3 of pNETs, demonstrating favorable interpretability. CLINICAL RELEVANCE STATEMENT: The radiomics-based interpretable model developed in this study has significant clinical relevance as it offers a non-invasive method for assessing the pathological grade of pancreatic neuroendocrine tumors and holds promise as an important complementary tool to traditional tissue biopsy. KEY POINTS: • A radiomics-based interpretable model was developed to predict the pathological grade of pNETs and compared with preoperative needle biopsy in terms of accuracy. • The model, based on CT radiomics, demonstrated favorable interpretability. • The radiomics model holds potential as a valuable complementary technique to preoperative needle biopsy; however, it should not be considered a replacement for biopsy.

Belzutifan: a novel therapeutic for the management of von Hippel-Lindau disease and beyond.

The identification of the VHL gene and its role in regulating the hypoxia-inducible factor signaling pathway has helped to revolutionize the treatment of renal cell carcinoma (RCC). Belzutifan is a novel small-molecule inhibitor of hypoxia-inducible factor 2α which has demonstrated efficacy in treating von Hippel-Lindau (VHL) disease, earning regulatory approvals for this indication. There is also early evidence for efficacy in sporadic RCC. Belzutifan has a favorable safety profile. Several clinical trials are currently ongoing, which should help in identifying this promising drug's role in RCC and beyond. This review summarizes the history, pharmacology and clinical evidence for belzutifan use to date, and also explores unanswered questions as they relate to this novel therapeutic agent.

The novel drug belzutifan was developed after years of research in identifying the VHL gene and how genetic abnormalities in VHL may result in tumor growth. Belzutifan has been approved for use in patients with VHL disease ­ a rare familial disorder first described in the 19th century that presents with a variety of cancerous and noncancerous tumors, including kidney cancer. Growing evidence supports belzutifan's use in non-familial kidney cancer as well. This is important because most patients eventually develop resistance to the currently available cancer treatments, highlighting the need for drugs with a different mechanism of action. Belzutifan works by blocking a protein called HIF-2a, which causes tumor growth in patients with VHL disease. Belzutifan is well tolerated, with the most common side effects being low energy, hemoglobin and blood oxygen. This review summarizes the history, mechanism of action and research evidence to date supporting the use of belzutifan in VHL disease and cancer treatment. We also discuss future directions, including remaining clinical questions and areas of ongoing research.

Management of Pancreatic Neuroendocrine Tumors: Surgical Strategies and Controversies.

OBJECTIVE: Pancreatic neuroendocrine tumors (PNETs) are uncommon tumors which are increasing in incidence. The management of these tumors continues to evolve. This review examines the current role of surgery in the treatment of these tumors. METHODS: Studies published over the past 10 years were identified using several databases including PubMed, MEDLINE, and Science Direct. Search terms included PNETs, treatment, and surgery. Clinical practice guidelines and updates from several major groups were reviewed. RESULTS: Surgery continues to have a major role in the treatment of sporadic functional and nonfunctional PNETs. Pancreas-sparing approaches are increasingly accepted as alternatives to formal pancreatic resection in selected patients. Options such as watch and wait or endoscopic ablation may be reasonable alternatives to surgery for non-functional PNETs < 2 cm in size. Surgical decision-making in multiple endocrine neoplasia type 1 patients remains complex and in some situations such as gastrinoma quite controversial. The role of surgery has significantly diminished in patients with advanced disease due to the advent of more effective systemic and liver-directed therapies. However, the optimal treatments and sequencing in advanced disease remain poorly defined, and it has been suggested that surgery is underutilized in these patients. CONCLUSIONS: Surgery remains a major treatment modality for PNETs. Given the plethora of available treatments, ongoing controversies and the changing landscape, management has become increasingly complex. An experienced multidisciplinary team which includes surgery is essential to manage these patients.

Characteristics and risk differences of different tumor sizes on distant metastases of pancreatic neuroendocrine tumors: A retrospective study in the SEER database.

BACKGROUND: The rate of distant metastasis in patients with pancreatic neuroendocrine tumors (PNETs) is 20%-50% at the time of initial diagnosis. However, whether tumor size can predict distant metastasis for PNETs remains unknown up to date. METHODS: We used Surveillance, Epidemiology, and End Results (SEER) population-based data to collect 6089 patients with PNETs from 2010 to 2019. The optimal cut-off point of tumor size to predict distant metastasis was calculated by Youden's index. Multivariate logistic regression analysis was used to figure out the association between tumor size and distant metastasis patterns. RESULTS: The most common metastatic site was liver (27.2%), followed by bone (3.0%), lung (2.3%) and brain (0.4%). Based on an optimal cut-off value of tumor size (25.5 mm) for predicting distant metastasis determined by Youden's index, patients were categorized into groups of tumor size < 25.5 mm and ≥ 25.5 mm. Multivariate logistic regression analyses showed that, compared with < 25.5 mm, tumor size ≥ 25.5 mm was an independent risk predictor of overall distant metastasis [odds ratio (OR) = 4.491, 95% confidence interval (CI): 3.724-5.416, P < 0.001] and liver metastasis (OR = 4.686, 95% CI: 3.886-5.651, P < 0.001). CONCLUSIONS: Tumor size ≥ 25.5 mm was significantly associated with more overall distant and liver metastases. Timely identification of distant metastasis for tumor size ≥ 25.5 mm may provide survival benefit for timely and precise treatment.

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.

Molecular Basis of Pancreatic Neuroendocrine Tumors.

Pancreatic neuroendocrine tumors (NETs) are rare well-differentiated neoplasms with limited therapeutic options and unknown cells of origin. The current classification of pancreatic neuroendocrine tumors is based on proliferative grading, and guides therapeutic strategies, however, tumors within grades exhibit profound heterogeneity in clinical manifestation and outcome. Manifold studies have highlighted intra-patient differences in tumors at the genetic and transcriptomic levels. Molecular classification might become an alternative or complementary basis for treatment decisions and reflect tumor biology, actionable cellular processes. Here, we provide a comprehensive review of genomic, transcriptomic, proteomic and epigenomic studies of pancreatic NETs to elucidate patterns shared between proposed subtypes that could form a foundation for new classification. We denote four NET subtypes with distinct molecular features, which were consistently reproduced using various omics technologies.

A dose escalation/expansion study evaluating dose, safety, and efficacy of the novel tyrosine kinase inhibitor surufatinib, which inhibits VEGFR 1, 2, & 3, FGFR 1, and CSF1R, in US patients with neuroendocrine tumors.

Surufatinib, is a potent inhibitor of vascular endothelial growth factor receptors 1-3; fibroblast growth factor receptor-1; colony-stimulating factor 1 receptor. This Phase 1/1b escalation/expansion study in US patients with solid tumors evaluated 5 once daily (QD) surufatinib doses (3 + 3 design) to identify maximum tolerated dose (MTD), recommended Phase 2 dose (RP2D), and evaluate safety and efficacy at the RP2D in 4 disease-specific expansion cohorts including pancreatic neuroendocrine tumors [pNET] and extrapancreatic NETs [epNET]. MTD and RP2D were 300 mg QD (escalation [n = 35]); 5 patients (15.6%) (Dose Limiting Toxicity [DLT] Evaluable Set [n = 32]) had DLTs. Pharmacokinetics were dose proportional. Estimated progression-free survival (PFS) rates at 11 months were 57.4% (95% confidence interval [CI]: 28.7, 78.2) and 51.1% (95% CI: 12.8, 80.3) for pNET and epNET expansion cohorts, respectively. Median PFS was 15.2 (95% CI: 5.2, not evaluable) and 11.5 (95% CI: 6.5,11.5) months. Response rates were 18.8% and 6.3%. The most frequent treatment-emergent adverse events (both cohorts) were fatigue (46.9%), hypertension (43.8%), proteinuria (37.5%), diarrhea (34.4%). Pharmacokinetics, safety, and antitumor efficacy of 300 mg QD oral surufatinib in US patients with pNETs and epNETs are consistent with previously reported studies in China and may support applicability of earlier surufatinib studies in US patients. Clinical trial registration: Clinicaltrials.gov NCT02549937.

Identification of the Immune Subtypes for the Prediction of Metastasis in Pancreatic Neuroendocrine Tumors.

INTRODUCTION: Most patients with pancreatic neuroendocrine tumors (pNETs) present with unresectable or metastatic disease. Increasing evidence shows that the immune cell infiltration patterns play a pivotal role in tumor progression in pNETs. Nonetheless, there has been no comprehensive analysis of the effect of immune infiltration patterns on metastasis. METHODS: The gene expression profiling dataset and clinical data were obtained from the Gene Expression Omnibus database. Estimation of Stromal and Immune Cells in Malignant Tumors using the Expression Data and single-sample Gene Set Enrichment Analysis were used to uncover the landscape of the tumor immune microenvironment. Subtypes based on the immune infiltration patterns were identified by the unsupervised clustering algorithm. Differentially expressed genes were identified using the limma packages of R. Functional enrichment analyses of these genes were carried out using STRING, Kyoto Encyclopedia of Genes and Genomes, and Reactome. RESULTS: The landscape of immune cells in pNET samples was constructed, and three immune cell infiltration subtypes (Immunity-H, Immunity-M, and Immunity-L) were identified. Immune cell infiltration degrees and metastasis were positively correlated. A protein-protein interaction network containing 80 genes was constructed, and functional enrichment revealed that these genes were mainly enriched in immune-related pathways. Eleven metastasis-related genes were differentially expressed among three subtypes, including MMP14, MMP2, MMP12, MMP7, SPARC, MMP19, ITGAV, MMP23B, MMP1, MMP25, and MMP9. There is a certain consistency of immune infiltration pattern between the primary tumor and metastatic tumor samples. CONCLUSION: Our findings may deepen the understanding of the immune-mediated regulatory mechanisms underlying pNETs and may provide some promising targets for immunotherapy.

Molecular and Functional Heterogeneity of Primary Pancreatic Neuroendocrine Tumors and Metastases.

INTRODUCTION: Treatment response to the standard therapy is low for metastatic pancreatic neuroendocrine tumors (PanNETs) mainly due to the tumor heterogeneity. We investigated the heterogeneity between primary PanNETs and metastases to improve the precise treatment. METHODS: The genomic and transcriptomic data of PanNETs were retrieved from the Genomics, Evidence, Neoplasia, Information, Exchange (GENIE), and Gene Expression Omnibus (GEO) database, respectively. Potential prognostic effects of gene mutations enriched in metastases were investigated. Gene set enrichment analysis was performed to investigate the functional difference. Oncology Knowledge Base was interrogated for identifying the targetable gene alterations. RESULTS: Twenty-one genes had significantly higher mutation rates in metastases which included TP53 (10.3% vs. 16.9%, p = 0.035) and KRAS (3.7% vs. 9.1%, p = 0.016). Signaling pathways related to cell proliferation and metabolism were enriched in metastases, whereas epithelial-mesenchymal transition (EMT) and TGF-ß signaling were enriched in primaries. Gene mutations were highly enriched in metastases that had significant unfavorable prognostic effects included mutation of TP53 (p < 0.001), KRAS (p = 0.001), ATM (p = 0.032), KMT2D (p = 0.001), RB1 (p < 0.001), and FAT1 (p < 0.001). Targetable alterations enriched in metastases included mutation of TSC2 (15.5%), ARID1A (9.7%), KRAS (9.1%), PTEN (8.7%), ATM (6.4%), amplification of EGFR (6.0%), MET (5.5%), CDK4 (5.5%), MDM2 (5.0%), and deletion of SMARCB1 (5.0%). CONCLUSION: Metastases exhibited a certain extent of genomic and transcriptomic diversity from primary PanNETs. TP53 and KRAS mutation in primary samples might associate with metastasis and contribute to a poorer prognosis. A high fraction of novel targetable alterations enriched in metastases deserves to be validated in advanced PanNETs.

Preoperative acute pancreatitis and hyperenzymemia are associated with poor prognosis in patients with nonfunctional pancreatic neuroendocrine tumors.

BACKGROUND: We aimed to investigate the prevalence of acute pancreatitis (AP) and hyperenzymemia as well as their clinical impact on postoperative survival outcomes in patients with pancreatic neuroendocrine tumors (PNETs). METHODS: A retrospective cohort study of 218 patients who underwent radical surgical resection for nonfunctional PNETs (NF-PNETs) was conducted. Multivariate survival analysis was performed by the Cox proportional hazard model, with results expressed as hazard ratio (HR) and 95% confidence interval (CI). RESULTS: Of the 151 patients who met the inclusion criteria, the incidences of preoperative AP and hyperenzymemia were 7.9% (12/152) and 23.2% (35/151), respectively. The mean recurrence-free survival (RFS, 95% CI) for patients in control, AP, and hyperenzymemia groups was 136 (127-144), 88 (74-103), and 90 (61-122) months, with a 5-year RFS rate of 86.5%, 58.3%, and 68.9%, respectively. In the multivariable-adjusted Cox hazard model that included tumor grade and lymph node status, the adjusted HR of AP and hyperenzymemia for recurrence was 2.58 (95% CI: 1.47-7.86, p = 0.008) and 2.43 (95% CI: 1.08-7.06, p = 0.040). CONCLUSION: Preoperative AP and hyperenzymemia are associated with poor RFS following radical surgical resection in NF-PNETs patients.

Clinical implications of cell-of-origin epigenetic characteristics in non-functional pancreatic neuroendocrine tumors.

Primary non-functional pancreatic neuroendocrine tumors (NF-PanNETs) are a heterogeneous group of neuroendocrine neoplasms that display highly variable clinical behavior. Therefore, NF-PanNETs often present clinical teams with a dilemma: the uncertain metastatic potential of the tumor has to be weighed against the morbidity associated with surgical resection. Thus, rather than utilizing current radiologic thresholds, there is an urgent need for improved prognostic biomarkers. Recent studies aimed at understanding the epigenetic underpinnings of NF-PanNETs have led to the identification of tumor subgroups based on histone modification and DNA methylation patterns. These molecular profiles tend to resemble the cellular origins of PanNETs. Subsequent retrospective analyses have demonstrated that these molecular signatures are of prognostic value and, importantly, may be useful in the preoperative setting. These studies have highlighted that sporadic NF-PanNETs displaying biomarkers associated with disease progression and poor prognosis, such as alternative lengthening of telomeres, inactivating alpha thalassemia/mental retardation X-linked (ATRX) or death domain-associated protein (DAXX) gene mutations, or copy number variations, more often display alpha cell characteristics. Conversely, NF-PanNETs with beta cell characteristics often lack these unfavorable biomarkers. Alternative lengthening of telomeres, transcription factor protein expression, and possibly DNA methylation can be assessed in endoscopic ultrasound-guided tumor biopsies. Prospective studies focusing on cell-of-origin and epigenetic profile-driven decision making prior to surgery are likely to be routinely implemented into clinical practice in the near future. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

The incidence, prevalence, and survival analysis of pancreatic neuroendocrine tumors in the United States.

PURPOSE: The incidence of pancreatic neuroendocrine tumors (pNETs) was increasing. The main purpose of this study was to statistically analyze the incidence and prevalence of pNETs and the main risk factors for the prognosis. METHODS: Based on the Surveillance, Epidemiology, and End Results (SEER) database, with three registries integrated, this study comprehensively displayed the annual age adjust incidence of pNETs from 1975 to 2018, the estimated 20-year limited-duration prevalence, and conducted the univariate and multivariate survival analysis. RESULTS: The incidence of pNETs has increased to about 1.5 per 100,000 population, and the prevalence has reached about 0.008% with the aged, Grade 1 and nonfunctional tumors accounting for the majority. The average median overall survival (OS), 5-year survival rate, and median disease-free survival (DFS) of pNETs patients from 1975 to 2018 were 85 months, 57.55%, and 220 months, respectively. From 2000 to 2018, the median OS was 94 months, and the 5-year survival rate was 59.94%. In multivariate survival analysis, the greatest risk factor was Grade 3&4 with HR = 3.62 (3.10-4.28), followed by distant stage with HR = 2.77 (2.28-3.36), and aged over 80 years old with HR = 2.26 (1.33-3.83). Surgery was a protective prognostic factor with HR = 0.34 (0.29-0.40). CONCLUSION: The incidence and prevalence of pNETs were still increasing, but the trend was gradual and aging in recent years. The survival time of pNETs was longer but has not changed much in recent years. The degrees of malignancy, stage, and operation were the most important prognosis factors.

Pancreatic neuroendocrine tumor progression and resistance to everolimus: the crucial role of NF-kB and STAT3 interplay.

PURPOSE: The finding of mTOR overactivation in patients affected by pancreatic neuroendocrine tumors (Pa-NETs) led to their treatment with the mTOR inhibitor everolimus. Unfortunately, the efficacy of everolimus is restricted by the occurrence of resistance. The mechanisms leading to Pa-NETs' progression and resistance are not well understood. Notably, chronic inflammation is implicated in NET development. NF-kB is involved in inflammation and drug resistance mechanisms through the activation of several mediators, including STAT3. In this respect, NF-κB and STAT3 interaction is implicated in the crosstalk between inflammatory and tumor cells. METHODS: We investigated the expression of NF-kB in different Pa-NETs by RT-qPCR and immunohistochemistry. Then, we studied the role of NF-κB and STAT3 interplay in QGP-1 cells. Subsequently, we assessed the impact of NF-κB and STAT3 inhibitors in QGP-1 cell proliferation and spheroids growth. Finally, we evaluated the implication of the NF-kB pathway in everolimus-resistant Pa-NET cells. RESULTS: We found that the increased NF-kB expression correlates  with a higher grade in Pa-NETs. The activation of the STAT3 pathway induced by TNFα is mediated by NF-kB p65. NF-kB p65 and STAT3 inhibitors decrease QGP-1 viability, spheroids growth, and Pa-NETs cell proliferation. These effects are maintained in everolimus-resistant QGP-1R cells. Interestingly, we found that NF-kB, STAT3, IL-8, and SOCS3 are overexpressed in QGP-1R compared to QGP-1. CONCLUSION: Since the NF-kB pathway is implicated in Pa-NETs' progression and resistance to everolimus, these data could explain the potential use of NF-kB as a novel therapeutic target in Pa-NET patients.

Apoptosis-related factors are relevant to progression of pancreatic neuroendocrine tumors.

BACKGROUND: Multidisciplinary therapy centered on antitumor drugs is indicated in patients with unresectable pancreatic neuroendocrine tumors (PanNET). However, the criteria for selection of optimal therapeutic agents is controversial. The aim of this study was to assess the malignancy of PanNET for optimal therapeutic drug selection. METHODS: Forty-seven patients with PanNET who underwent surgery were reviewed retrospectively, and immunohistochemical characteristics, including expression of GLUT1, SSTR2a, SSTR5, Survivin, X-chromosome-linked inhibitor of apoptosis protein (XIAP), and Caspase3 in the resected specimens, were investigated. Relapse-free survival (RFS) and overall survival (OS) were evaluated with regard to the characteristics using the Kaplan-Meier method and compared with the log-rank test. RESULTS: GLUT1 expression showed significant correlation with sex (p = 0.036) and mitotic rate (p = 0.048). Survivin and XIAP expression showed significant correlation with T-stage (p = 0.014 and 0.009), p-Stage (p = 0.028 and 0.045), and mitotic rate (p = 0.023 and 0.007). XIAP expression also significantly influenced OS (p = 0.044). CONCLUSIONS: Survivin and XIAP correlated with grade of malignancy, and expression of XIAP in particular was associated with a poor prognosis. Expression of these proteins may be a useful indicator to select optimal therapeutic agents in PanNET.

Improving fine needle aspiration to predict the tumor biological aggressiveness in pancreatic neuroendocrine tumors using Ki-67 proliferation index, phosphorylated histone H3 (PHH3), and BCL-2.

INTRODUCTION: Surgery is the only known cure for sporadic pancreatic neuroendocrine tumors (PNETs). Therefore, the prediction of the PNETs biological aggressiveness evaluated on endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has a significant impact on clinical management. The proliferation rate of Ki-67 in PNETs can help to predict the biological aggressiveness of the tumor. In addition, there is a relatively new proliferation marker called phosphorylated histone H3 (PHH3) that can identify and quantify dividing cells in tissue samples, which is a marker highly specific to mitotic figures. Other markers such as BCL-2 also contribute to tumorigenesis and may be involved in the differentiation of neuroendocrine cells. MATERIALS AND METHODS: A retrospective observational study was performed on patients undergoing surveillance for PNETs from January 2010 to May 2021. Data collection included the patients' age, sex, tumor location, tumor size in the surgical specimen, and tumor grade in FNA. The 2019 World Health Organization (WHO) classification guideline was followed to diagnose PNETs, including grade and stage. Immunohistochemical stainings for Ki-67, PHH3 and BCL-2 in PNETs were performed. RESULTS: After excluding cell blocks containing fewer than 100 tumor cells, 44 patients with EUS-FNA and surgical resection specimens were included in this study. There were 19 cases of G1 PNETs, 20 cases of G2 PNETs, and 5 cases of G3 PNETs. The grade assigned based on the Ki-67 index was higher and more sensitive than that based on the mitotic count using H&E slides in some cases of G2 and G3 PNETs. However, there was no significant difference between the mitotic count using PHH3-positive tumor cells and the Ki-67 index to grade PNETs. All grade 1 tumors (19 cases) on surgical resection specimens were correctly graded on FNA (100 % concordance rate). Within the 20 G2 PNETs, 15 cases of grade 2 on surgical resection specimens were graded correctly on FNA based on the Ki-67 index only. Five cases of grade 2 PNETs on surgical resection specimens were graded as grade 1 on FNA when using only the Ki-67 index. Three of five grade 3 tumors on surgical resection specimens were graded as grade 2 on FNA based on the Ki-67 index only. Using only FNA Ki-67 to predict PNET tumor grade, the concordance (accuracy) rate was 81.8 % in total. However, all these eight cases (5 cases of G2 PNETs and 3 cases of G3 PNETs) were graded correctly by using the Ki-67 index plus mitotic rate (using PHH3 IHC stains). Four of 18 (22.2 %) patients with PNETs were positive for BCL-2 stain. In these 4 cases positive for BCL-2 stains, 3 cases were G2 PNETs and one case was G3 PNETs. CONCLUSION: Grade and the proliferative rate in EUS-FNA can be used to predict the tumor grade in surgical resection specimens. However, when using only FNA Ki-67 to predict PNET tumor grade, about 18 % of cases were downgraded by one level. To solve the problem, immunohistochemical staining for BCL-2 and especially PHH3 would be helpful. Our results demonstrated that the mitotic count using PHH3 IHC stains not only improved the accuracy and precision of PNET grading in the surgical resection specimens, but also could reliably be used in routine scoring of mitotic figures of FNA specimens.

Efficacy and Safety of Endoscopic Ultrasound-Guided Radiofrequency Ablation for Pancreatic Neuroendocrine Tumors: A Systematic Review and Metanalysis.

Introduction: The development of dedicated endoscopes and the technical evolution of endoscopic ultrasound (EUS) have allowed a direct approach to pancreatic neoplastic lesions both for diagnosis and treatment. Among the more promising targets are pancreatic neuroendocrine tumors (Pan-NETs). Aim: to describe the evolution of endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) with particular attention to the treatment of PanNETs, focusing on safety and clinical efficacy of the technique. Methods: MEDLINE, Scopus, and Cochrane Library databases were searched for studies reporting about EUS-RFA for the treatment of PanNETs. Studies with outcomes of interest were selected and results were reported to describe clinical success, complications, fol-low-ups, and electrodes used. Clinical success was defined as the disappearance of clinical symp-toms for functional (F-) PanNETs and as complete ablation per nonfunctional (NF)-PanNETs. The pooled data were analyzed by a random-effects model. Results: Nineteen studies were selected, including 183 patients (82 males, 44.8%) with 196 lesions (101 F-PanNETs and 95 NF-PanNETs). Pooled estimates for the overall AE rates for the clinical efficacy were 17.8% (95% CI 9.1-26.4%) and 95.1% (95% CI 91.2-98.9%) for F-PanNETs and 24.6% (95% CI 7.4-41.8%) and 93.4% (95% CI 88.4-98.4%) for NF-PanNETs. Conclusions: EUS-RFA appears to be a mini-invasive technique with a good safety and efficacy profile for the treatment of F- and NF-PanNETs. EUS-RFA could be of-fered as possible alternative to surgery for the treatment of low-grade NF- or F-PanNETs, especially for those patients that are not eligible or are at high-risk for surgery.