Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare and highly heterogeneous neoplasms whose incidence has markedly increased over the last decades. A grading system based on the tumor cells’ proliferation index predicts high-risk for G3 NETs. However, low-to-intermediate grade (G1/G2) NETs have an unpredictable clinical course that varies from indolent to highly malignant. Cultures of human cancer cells enable to perform functional perturbation analyses that are instrumental to enhance our understanding of cancer biology. To date, no tractable and reliable long-term culture of G1/G2 NET has been reported to permit disease modeling and pharmacological screens. Here, we report of the first long-term culture of a G2 metastatic small intestinal NET that preserves the main genetic drivers of the tumor and retains expression patterns of the endocrine cell lineage. Replicating the tissue, this long-term culture showed a low proliferation index, and yet it could be propagated continuously without dramatic changes in the karyotype. The model was readily available for pharmacological screens using targeted agents and as expected, showed low tumorigenic capacity in vivo. Overall, this is the first long-term culture of NETs to faithfully recapitulate many aspects of the original neuroendocrine tumor.

Myeloid cells can restrain antitumor immunity by metabolic pathways, such as the degradation of l-arginine, whose concentrations are regulated by the arginase 1 (ARG1) enzyme. Results from preclinical studies indicate the important role of arginine metabolism in pancreatic ductal adenocarcinoma (PDAC) progression, suggesting a potential for clinical application; however, divergent evolution in ARG1 expression and function in rodents and humans has restricted clinical translation. To overcome this dichotomy, here, we show that neutrophil extracellular traps (NETs), released by spontaneously activated neutrophils isolated from patients with PDAC, create a microdomain where cathepsin S (CTSS) cleaves human (h)ARG1 into different molecular forms endowed with enhanced enzymatic activity at physiological pH. NET-associated hARG1 suppresses T lymphocytes whose proliferation is restored by either adding a hARG1-specific monoclonal antibody (mAb) or preventing CTSS-mediated cleavage, whereas small-molecule inhibitors are not effective. We show that ARG1 blockade, combined with immune checkpoint inhibitors, can restore CD8+ T cell function in ex vivo PDAC tumors. Furthermore, anti-hARG1 mAbs increase the frequency of adoptively transferred tumor-specific CD8+ T cells in tumor and enhance the effectiveness of immune checkpoint therapy in humanized mice. Thus, this study shows that extracellular ARG1, released by activated myeloid cells, localizes in NETs, where it interacts with CTSS that in turn cleaves ARG1, producing major molecular forms endowed with different enzymatic activity at physiological pH. Once exocytosed, ARG1 activity can be targeted by mAbs, which bear potential for clinical application for the treatment of PDAC and require further exploration.

Transcriptomic analyses of pancreatic ductal adenocarcinoma (PDAC) have identified two major epithelial subtypes with distinct biology and clinical behaviours. Here, we aimed to clarify the role of FGFR1 and FGFR4 in the definition of aggressive PDAC phenotypes. We found that the expression of FGFR4 is exclusively detected in epithelial cells, significantly elevated in the classical PDAC subtype, and associates with better outcomes. In highly aggressive basal-like/squamous PDAC, reduced FGFR4 expression aligns with hypermethylation of the gene and lower levels of histone marks associated with active transcription in its regulatory regions. Conversely, FGFR1 has more promiscuous expression in both normal and malignant pancreatic tissues and is strongly associated with the EMT phenotype but not with the basal-like cell lineage. Regardless of the genetic background, the increased proliferation of FGFR4-depleted PDAC cells correlates with hyperactivation of the mTORC1 pathway both in vitro and in vivo. Downregulation of FGFR4 in classical cell lines invariably leads to the enrichment of basal-like/squamous gene programs and is associated with either partial or full switch of phenotype. In sum, we show that endogenous levels of FGFR4 limit the malignant phenotype of PDAC cells. Finally, we propose FGFR4 as a valuable marker for the stratification of PDAC patients.

Here we report the DNA methylation profile of 84 sporadic pancreatic neuroendocrine tumors (PanNETs) with associated clinical and genomic information. We identified three subgroups of PanNETs, termed T1, T2 and T3, with distinct patterns of methylation. The T1 subgroup was enriched for functional tumors and ATRX , DAXX and MEN1 wild-type genotypes. The T2 subgroup contained tumors with mutations in ATRX , DAXX and MEN1 and recurrent patterns of chromosomal losses in half of the genome with no association between regions with recurrent loss and methylation levels. T2 tumors were larger and had lower methylation in the MGMT gene body, which showed positive correlation with gene expression. The T3 subgroup harboured mutations in MEN1 with recurrent loss of chromosome 11, was enriched for grade G1 tumors and showed histological parameters associated with better prognosis. Our results suggest a role for methylation in both driving tumorigenesis and potentially stratifying prognosis in PanNETs.

The GNA15 gene is ectopically expressed in human pancreatic ductal adenocarcinoma cancer cells. The encoded Gα15 protein can promiscuously redirect GPCR signaling toward pathways with oncogenic potential. We sought to describe the distribution of GNA15 in adenocarcinoma from human pancreatic specimens and to analyze the mechanism driving abnormal expression and the consequences on signaling and clinical follow-up. We detected GNA15 expression in pre-neoplastic pancreatic lesions and throughout progression. The analysis of biological data sets, primary and xenografted human tumor samples, and clinical follow-up shows that elevated expression is associated with poor prognosis for G NA 15 , but not any other GNA gene. Demethylation of the 5′ GNA15 promoter region was associated with ectopic expression of Gα15 in pancreatic neoplastic cells, but not in adjacent dysplastic or non-transformed tissue. Down-modulation of Gα15 by shRNA or CRISPR/Cas9 affected oncogenic signaling, and reduced adenocarcimoma cell motility and invasiveness. We conclude that de novo expression of wild-type GNA15 characterizes transformed pancreatic cells. The methylation pattern of GNA15 changes in preneoplastic lesions coincident with the release a transcriptional blockade that allows ectopic expression to persist throughout PDAC progression. Elevated GNA15 mRNA correlates with poor prognosis. In addition, ectopic Gα15 signaling provides an unprecedented mechanism in the early steps of pancreas carcinogenesis distinct from classical G protein oncogenic mutations described previously in GNAS and GNAQ/GNA11 .

BACKGROUND:Extrahepatic cholangiocarcinoma (ECC) is classified into two subtypes based on anatomic origin: distal extrahepatic (DECC) and perihilar (PHCC) cholangiocarcinoma. This study aimed to shed light on its genomic and transcriptomic profiles. RESEARCH DESIGN AND METHODS:The genomic alterations of 99 ECC (47 PHCC and 52 DECC) were investigated by next-generation sequencing of 96 genes. A subgroup of cases, representative of each subtype, was further investigated using transcriptomic analysis. Bioinformatics tools were applied for clustering and pathway analysis and defining the immune composition of the tumor microenvironment. RESULTS:PHCC had more frequent KRAS mutations (p = 0.0047), whereas TP53 mutations were more common in DECC (p = 0.006). Potentially actionable alterations included high-tumor mutational burden and/or microsatellite instability (7.1%), PI3KCA mutations (8.1%), and MYC (10.1%) and ERBB2 amplification (5.1%). The transcriptomic profiles showed the presence of three distinct clusters, which followed the anatomic origin and differed in immune microenvironment. DECC appeared to contain two distinct tumor subgroups, one enriched for druggable alterations and one lacking actionable opportunities. CONCLUSIONS:This study provides new insights into the molecular landscape and the actionable alterations of ECC. Our findings represent a step toward improved ECC molecular taxonomy and therapeutic strategies for precision oncology.

Background: The pattern of nodal spread in body-tail pancreatic ductal adenocarcinoma (PDAC) has been poorly investigated. This study analyzed the characteristics of lymph node (LN) involvement and the prognostic role of nodal metastases stratified by LN stations. Methods: All upfront distal pancreatectomies (DPs) for PDAC (2000-2017) with complete information on station 8,10,11, and 18 were included. Clinico-pathological correlates and survival were investigated using uni- and multivariable analyses. Results: Among 100 included patients, 28 were NO, 42 N1 and 30 N2. The median number of examined LN was 32 (IQR 26-44). Tumor size at preoperative imaging increased across N-classes. Preoperative size >27.5 mm was associated with N2 status. The frequency of nodal metastases at stations 8, 9, 10, 11, and 18 was 12.0%, 10.9%, 3.0%, 71.0%, and 19%, respectively. The pattern of LN spread was independent from primary tumor location (with tail tumors metastasizing to station 8/9 and body tumors to station 10), while it was highly associated with N-class. At multivariable analysis, tumor grading, adjuvant treatment, station 9 and 10 metastases were independent prognostic factors in node-positive patients. Conclusions: In patients undergoing upfront DP for PDAC preoperative tumor size is associated with the degree of nodal spread. While station 11 was the most frequently involved, only station-9 and 10 metastases were independent prognostic factors. The site of nodal metastases was somewhat unpredictable based on tumor location. This data has potential implications for allocating patients to neoadjuvant treatment and supports the performance of routine splenectomy during DP for PDAC. (C) 2020 Elsevier Ltd, BASO similar to The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.

The aim of the present study was to investigate the relationship between the mutational gene profile and recurrence in biliary tract cancers (BTC). A total of 103 specimens of patients with BTC, who underwent curative surgery in a single tertiary HPB surgery referral center from 1990 to 2012, were assessed for mutational status in 52 cancer-related genes. Considering the different types of BTC, the 5-year recurrence-free survival (RFS) rate was 16.7% (median RFS 7 months) in gallbladder cancer, 42.9% (median RFS 26.4 months) in intrahepatic cholangiocarcinoma, and 19.7% (median RFS 16.5 months) in perihilar cholangiocarcinoma, p = 0.166. At the multivariate analysis including clinical, pathological, and molecular features, the factors independently related to RFS were radicality of surgery (OR 2.050, CI 1.104–3.807, p = 0.023), LN status (OR 1.835, CI 1.006–3.348, p = 0.048), mutational status of ARID1A (OR 2.566, CI 1.174–5.608, p = 0.018), and TP53 (OR 2.805, CI 4.432–5.496, p = 0.003). ARID1A mutation was associated with a local and systemic recurrence in the 43% and 29% of cases, respectively; and TP53 mutation was associated with a local and systemic recurrence in the 29% and 41% of cases. Moreover, TP53 was most commonly mutated in tumor of patients with early recurrence, p = 0.044. ARID1A and TP53 mutations seem to be related to poor outcome after surgery and may be considered molecular predictors of the biological aggressiveness in BTC.

Early onset pancreatic cancer (EOPC) is a rare disease with a very high mortality rate. Almost nothing is known on the genetic susceptibility of EOPC, therefore, we performed a genome-wide association study (GWAS) to identify novel genetic variants specific for patients diagnosed with pancreatic ductal adenocarcinoma (PDAC) at younger ages. In the first phase, conducted on 821 cases with age of onset <= 60 years, of whom 198 with age of onset <= 50, and 3227 controls from PanScan I-II, we observed four SNPs (rs7155613, rs2328991, rs4891017 and rs12610094) showing an association with EOPC risk (P < 1 x 10(-4)). We replicated these SNPs in the PANcreatic Disease ReseArch (PANDoRA) consortium and used additional in silico data from PanScan III and PanC4. Among these four variants rs2328991 was significant in an independent set of 855 cases with age of onset <= 60 years, of whom 265 with age of onset <= 50, and 4142 controls from the PANDoRA consortium while in the in silico data, we observed no statistically significant association. However, the resulting meta-analysis supported the association (P = 1.15 x 10(-4)). In conclusion, we propose a novel variant rs2328991 to be involved in EOPC risk. Even though it was not possible to find a mechanistic link between the variant and the function, the association is supported by a solid statistical significance obtained in the largest study on EOPC genetics present so far in the literature.

Pancreatic ductal adenocarcinoma (PDAC) is highly refractory to systemic treatment, including radiotherapy (RT) either as alone or in combination with chemotherapy. Magnetic resonance (MR)-guided RT is a novel treatment technique which conjugates the high MR imaging contrast resolution to the possibility of re-adapting treatment plan to daily anatomical variations. Magnetic field (MF) might exert a biological effect that could be exploited to enhance radiation effect. The aim of the present study was to lay the preclinical basis of the MF effect by exploring how it modifies the response to radiation in organoid cultures established from PDAC. The short-term effect of radiation, alone or in combination with MF, was evaluated in patient-derived organoids (PDOs) and monolayer cell cultures. Cell viability, apoptotic cell death, and organoid size following exposure to the treatment were evaluated. PDOs demonstrated limited sensitivity at clinically relevant doses of radiation. The combination of radiation and MF demonstrated superior efficacy than monotherapy in almost all the PDOs tested. PDOs treated with combination of radiation and MF were significantly smaller in size and some showed increased cell death as compared to the monotherapy with radiation. Long-time exposure to 1.5T MF can increase the therapeutic efficacy of radiation in PDAC organoids.

Cystic neoplasms of the pancreas are an increasingly important public health problem. The majority of these lesions are benign but some progress to invasive pancreatic ductal adenocarcinoma (PDAC). There is a dearth of mouse models of these conditions. The orphan nuclear receptor NR5A2 regulates development, differentiation, and inflammation. Germline Nr5a2 heterozygosity sensitizes mice to the oncogenic effects of mutant Kras in the pancreas. Here, we show that - unlike constitutive Nr5a2+/- mice - conditional Nr5a2 heterozygosity in pancreatic epithelial cells, combined with mutant Kras (KPN+/- ), leads to a dramatic replacement of the pancreatic parenchyma with cystic structures and an accelerated development of high-grade PanINs and PDAC. Timed histopathological analyses indicated that in KPN+/- mice PanINs precede the formation of cystic lesions and the latter precede PDAC. A single episode of acute caerulein pancreatitis is sufficient to accelerate the development of cystic lesions in KPN+/- mice. Epithelial cells of cystic lesions of KPN+/- mice express MUC1, MUC5AC, and MUC6, but lack expression of MUC2, CDX2, and acinar markers, indicative of a pancreato-biliary/gastric phenotype. In accordance with this, in human samples we found a non-significantly decreased expression of NR5A2 in mucinous tumours, compared with conventional PDAC. These results highlight that the effects of loss of one Nr5a2 allele are time- and cell context-dependent. KPN+/- mice represent a new model to study the formation of cystic pancreatic lesions and their relationship with PanINs and classical PDAC. Our findings suggest that pancreatitis could also contribute to acceleration of cystic tumour progression in patients. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

The intraductal oncocytic papillary neoplasm (IOPN) of the pancreas has been recognized by WHO classification as a unique intraductal papillary mucinous neoplasm (IPMN) category. IOPN is composed of oxyphil cells, usually expressing MUC5AC, MUC6, and Hep Par-1, and harboring PRKACA/B fusion genes as their genetic hallmark. Although IOPNs are associated with an infiltrative adenocarcinoma in up to 30% of cases, the survival rate after surgical resection approaches 100%. This highlights the importance of the correct IOPN diagnosis, above all in cases with an associated invasive component. In this study, the immunohistochemical expression of CD117 was investigated in 111 IPMNs, including 17 oncocytic, 45 gastric, 20 pancreatico-biliary, and 29 intestinal IPMNs. We also tested the expression of MUC5AC, MUC6, and Hep Par-1 in the IOPN cohort. CD117 positivity was significantly more frequent in IOPNs compared to the other IPMN subtypes (p < 0.0001). Furthermore, within IOPN, a lower or absent CD117, MUC5AC, MUC6, and Hep Par-1 expression tended to be associated with the presence of an infiltrative component. Our findings shed light into the biology of these complex lesions, which are confirmed to be a distinctive IPMN subtype; notably, CD117 emerged as a potential, additional tool in the differential diagnosis of IPMNs.

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer-related mortality among adults in developed countries. The discovery of the most common genetic alterations as well as the development of organoid models of pancreatic cancer have provided insight into the fundamental pathways driving tumor progression from a normal cell to non-invasive precursor lesion and finally to widely metastatic disease, offering new opportunities for identifying the key driver of cancer evolution. Obesity is one of the most serious public health challenges of the 21st century. Several epidemiological studies have shown the positive association between obesity and cancer-related morbidity/mortality, as well as poorer prognosis and treatment outcome. Despite strong evidence indicates a link between obesity and cancer incidence, the molecular basis of the initiating events remains largely elusive. This is mainly due to the lack of an accurate and reliable model of pancreatic carcinogenesis that mimics human obesity-associated PDAC, making data interpretation difficult and often confusing. Here we propose a feasible and manageable organoid-based preclinical tool to study the effects of obesity on pancreatic carcinogenesis. Therefore, we tracked the effects of obesity on the natural evolution of PDAC in a genetically defined transplantable model of the syngeneic murine pancreatic preneoplastic lesion (mP) and tumor (mT) derived-organoids that recapitulates the progression of human disease from early preinvasive lesions to metastatic disease. Our results suggest that organoid-derived transplant in obese mice represents a suitable system to study early steps of pancreatic carcinogenesis and supports the hypothesis that inflammation induced by obesity stimulates tumor progression and metastatization during pancreatic carcinogenesis.

Assessing intra-tumoral heterogeneity (ITH) is of paramount importance to anticipate failure of targeted therapies and design accordingly effective anti-tumor strategies. Although concerns are frequently raised due to differences in sample processing and depth of coverage, next-generation sequencing of solid tumors have unraveled a highly variable degree of ITH across tumor types. Capturing the genetic relatedness between primary and metastatic lesions through the identification of clonal and subclonal populations is critical to the design of therapies for advance-stage diseases. Here, we report a method for comparative lesions analysis that allows for the identification of clonal and subclonal populations among different specimens from the same patient. The experimental approach described here integrates three well-established approaches: histological analysis, high-coverage multi-lesion sequencing, and immunophenotypic analyses. In order to minimize the effects on the detection of subclonal events by inappropriate sample processing, we subjected tissues to careful pathological examination and neoplastic cell enrichment. Quality controlled DNA from neoplastic lesions and normal tissues was then subjected to high coverage sequencing, targeting the coding regions of 409 relevant cancer genes. While only looking at a limited genomic space, our approach enables evaluating the extent of heterogeneity among somatic alterations (single-nucleotide mutations and copy-number variations) in distinct lesions from a given patient. Through comparative analysis of sequencing data, we were able to distinguish clonal vs. subclonal alterations. The majority of ITH is often ascribed to passenger mutations; therefore, we also used immunohistochemistry to predict functional consequences of mutations. While this protocol has been applied to a specific tumor type, we anticipate that the methodology described here is broadly applicable to other solid tumor types.

Background: Two recent studies based on multi-omics data analysis identified distinct subtypes of bile-duct cancers (BDC) with important implications in terms of disease classification and patients' treatment. Methods: Patients with mutations in KRAS, NRAS, TP53, and ARID1A genes were classified in KRAS/TP53 group while patients with mutations in IDH1-2, BAP1, and PBRM1 were classified in IDH1-2/BAP1/PBRM1 group. The aim of this study was to define long-term outcomes among patients stratified by patterns of genes mutated. Results: Among 105 patients who underwent surgical resection for BDCs, 71 (68%) patients were classified in two groups based on patterns of genes mutated. While in IDH1-2/BAP1/PBRM1 group there were 58%, 22%, and 10% of patients with intrahepatic-cholangiocarcinoma (ICC), perihilar-cholangiocarcinoma (PHCC), and gallbladder cancer (GBC), in KRAS/TP53 group there were 42%, 78%, and 90% of patients with ICC, PHCC, and GBC (p = 0.003), respectively. Patients in IDH1-2/BAP1/PBRM1 group had a 5-year OS of 40% compared with 13% for KRAS/TP53 group (p = 0.032). In a multivariable model adjusted for margins, lymph-node status, microvascular invasion, and tumor grade, patients in KRAS/TP53 group had a 2.1-fold increased risk of death compared with patients in IDH1-2/BAP1/PBRM1 group (p = 0.028). Conclusions: Genetic data were able to overcome the clinical based staging system in predicting patients' prognosis.

OBJECTIVE:First, to assess the impact of the number of examined lymph nodes (ELNs) on staging and survival after distal pancreatectomy (DP) for pancreatic adenocarcinoma (PDAC). Second, to identify the minimum number of ELNs (MNELNs) ensuring an accurate detection of nodal involvement. Third, to reappraise the role of lymph node (LN) parameters, including N-status and lymph node ratio (LNR).BACKGROUND:In contrast with pancreatoduodenectomy, information on LN staging and the MNELN required in DP is lacking.METHODS:Patients undergoing DP for PDAC at 2 academic hospitals from 2000 through 2013 were retrospectively analyzed. The eighth edition of the American Joint Committee on Cancer staging system was used. The MNELN was estimated using the binomial probability law. Survival analyses were performed separately for node-negative and node-positive patients using univariable and multivariable models.RESULTS:The study population consisted of 240 patients. The median number of ELN was 21, significantly lower in node-negative patients as compared with node-positive patients (18.5 vs 24.0; P = 0.001). The proportion of node-positive patients increased with increasing numbers of ELNs, whereas LNR showed an inverse trend. The estimated MNELN was 20. The number of ELN (≥ or <20) was an independent prognostic factor only in node-negative patients [odds ratio (OR) 3.23 for ELN <20), suggesting a stage migration effect. In node-positive patients, N2-class, but not LNR, was a significant predictor of survival at multivariable analysis (OR 1.68).CONCLUSION:The number of ELN affects nodal staging in body/tail PDAC. At least 20 LNs are required for correct staging. N-status is superior to LNR in predicting survival of node-positive patients.

INTRODUCTION:DNA mutational profiling showed that atypical carcinoids (ACs) share alterations with large cell neuroendocrine carcinomas (LCNECs). Transcriptomic studies suggested that LCNECs are composed of two subtypes, one of which shares molecular anomalies with SCLC. The missing piece of information is the transcriptomic relationship between ACs and LCNECs, as a direct comparison is lacking in the literature. METHODS:Transcriptomic and genomic alterations were investigated by next-generation sequencing in a discovery set of 14 ACs and 14 LCNECs and validated on 21 ACs and 18 LCNECs by using custom gene panels and immunohistochemistry for Men1 and Rb1. RESULTS:A 58-gene signature distinguished three transcriptional clusters. Cluster 1 comprised 20 LCNECs and one AC harboring concurrent inactivation of tumor protein p53 gene (TP53) and retinoblastoma 1 gene (RB1) in the absence of menin 1 gene (MEN1) mutations; all cases lacked Rb1 nuclear immunostaining. Cluster 3 included 20 ACs and four LCNECs lacking RB1 alterations and having frequent MEN1 (37.5%) and TP53 mutations (16.7%); menin nuclear immunostaining was lost in 75% of cases. Cluster 2 included 14 ACs and eight LCNECs showing intermediate features: TP53, 40.9%; MEN1, 22.7%; and RB1, 18.2%. Patients in cluster C1 had a shorter cancer-specific survival than did patients in C2 or C3. CONCLUSIONS:ACs and LCNECs comprise three different and clinically relevant molecular diseases, one AC-enriched group in which MEN1 inactivation plays a major role, one LCNEC-enriched group whose hallmark is RB1 inactivation, and one mixed group with intermediate molecular features. These data support a progression of malignancy that may be traced by using combined molecular and immunohistochemical analysis.