Despite recent efforts to dissect the inter-tumor heterogeneity of pancreatic ductal adenocarcinoma (PDAC) by determining prognosis-predictive gene expression signatures for specific subtypes, their functional differences remain elusive. Here, we established a pancreatic tumor organoid library encompassing 39 patient-derived PDACs and identified 3 functional subtypes based on their stem cell niche factor dependencies on Wnt and R-spondin. A Wnt-non-producing subtype required Wnt from cancer-associated fibroblasts, whereas a Wnt-producing subtype autonomously secreted Wnt ligands and an R-spondin-independent subtype grew in the absence of Wnt and R-spondin. Transcriptome analysis of PDAC organoids revealed gene-expression signatures that associated Wnt niche subtypes with GATA6-dependent gene expression subtypes, which were functionally supported by genetic perturbation of GATA6. Furthermore, CRISPR-Cas9-based genome editing of PDAC driver genes (KRAS, CDKN2A, SMAD4, and TP53) demonstrated non-genetic acquisition of Wnt niche independence during pancreas tumorigenesis. Collectively, our results reveal functional heterogeneity of Wnt niche independency in PDAC that is non-genetically formed through tumor progression.

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ObjectiveEndoscopic papillectomy is increasingly being used for ampullary adenoma treatment. However, it remains challenging despite increased safety with treatment advances. The ideal power output and electrosurgical current mode for mucosal resection are not established. We aimed to identify the ideal electrical pulse for use during resection.MethodsThis pilot randomized, single‐blind, prospective, multicenter trial, recruited patients with ampullary adenomas and conventional anatomy who were scheduled to undergo endoscopic papillectomy. Endoscopic treatment was performed using a standardized algorithm and patients were randomized for endoscopic papillectomy with Endocut or Autocut. The primary outcome was the incidence of delayed bleeding. Incidence of procedure‐related pancreatitis, successful complete resection, pathological findings, and other adverse events were secondary endpoints.ResultsSixty patients were enrolled over a 2‐year period. The incidences of delayed bleeding (13.3% vs. 16.7%, P = 1.00) and pancreatitis (27% vs. 30%, P = 0.77) were similar between both groups. The rate of crush artifacts was higher in the Endocut than in the Autocut group (27% vs. 3.3%, P = 0.03). Immediate bleeding when resecting tumors greater than 14 mm in diameter was more common in the Autocut than in the Endocut group (88% vs. 46%, P = 0.04).ConclusionsThe Autocut and Endocut modes have similar efficacy and safety for endoscopic papillectomy. The Endocut mode may prevent immediate bleeding in cases with large tumor sizes, although it causes more frequent crush artifacts.Registry and the registration numberThe Japanese UMIN Clinical Trials Registry (UMIN‐CTR: 000021382).

Background and Aims Endoscopic submucosal dissection (ESD) for superficial duodenal epithelial tumors (SDETs) is technically difficult and has a high risk of adverse events. Endoscopic nasobiliary and nasopancreatic duct drainage (ENBPD) may reduce the risk of delayed adverse events by preventing exposure of the post‐ESD mucosal defect to bile and pancreatic juice. This study was performed to evaluate the safety and feasibility of ENBPD after duodenal ESD. Methods Patients who underwent ESD for SDETs from July 2010 to March 2020 were included. We collected data on the success rate of ENBPD, adverse events due to insertion of a side‐viewing endoscope, and pancreatitis after ENBPD. We also collected the clinical outcomes of duodenal ESD, including the incidence rate of delayed adverse events (defined as bleeding or perforation found after the endoscopic procedure). Results Among 70 patients without complete closure of the post‐ESD mucosal defect, ENBPD was successfully performed in all 25 patients including 21 cases inserted immediately after ESD and four cases inserted later. There were no adverse events associated with ENBPD procedure intraoperatively, while pancreatitis after ENBPD occurred in four patients (16.0%). No patients who underwent immediate ENBPD required intervention for an intra‐abdominal abscess or delayed perforation, whereas 3 of 49 patients (6.1%) who did not undergo immediate ENBPD required surgery or drainage of an abscess. Conclusions Endoscopic nasobiliary and nasopancreatic duct drainage is technically feasible and might provide effective prophylaxis for delayed adverse events, even if a large mucosal defect is present after ESD.

Background and study aims  Endoscopic papillectomy (EP) is a minimally invasive treatment for ampullary neoplasms and is recognized as an alternative treatment to surgical resection; however, there are few reports on a suitable pancreatic stent (PS) after EP for preventing pancreatitis. The aim of this study was to evaluate the efficacy of a long PS after EP. Patients and methods  In this retrospective single-center study, 39 patients with pathologically proven ampullary neoplasms who underwent EP between March 2012 and August 2018 were enrolled. The study participants were divided into two subgroups according to the PS length: those with a PS shorter than 5 cm (short PS group, n = 17) and those with a PS of 7 cm (long PS group, n = 22). The incidence of adverse events and risk factors for pancreatitis were evaluated. Results  The diameter of all PSs was 5 Fr. Post-EP pancreatitis occurred in nine patients (23.1 %), with two cases of severe pancreatitis (5.1 %). Pancreatitis occurred more frequently in the short PS group (7/17, 41.2 %) than in the long PS group (2/22, 9.1 %) ( P  = 0.026). There were no significant differences between the two groups in terms of other adverse events. Univariate and multivariate analyses showed that a long PS was the only factor associated with a decreased incidence of post-EP pancreatitis ( P  = 0.042; odds ratio, 0.16; 95 % confidence interval, 0.027–0.94). Conclusion  A long (7 cm) PS significantly decreased incidence of pancreatitis after EP. Prospective randomized studies with a larger number of patients and wider range of PS lengths are required.

Objective Risks of bleeding and pancreatitis after mucosal resection using the purecut/autocut and blendcut/endocut modes for endoscopic papillectomy have not been fully clarified. Thus, a systematic review on electrosurgical cutting modes for endoscopic papillectomy was conducted focusing on the types and incidence of adverse events. Methods We searched the PubMed and Cochrane library for cases of endoscopic papillectomy recorded as of April 2017. Studies reporting the methods of electrically excising a tumor in the duodenal papilla and the number of adverse events were extracted. Studies were collected and examined separately based on the electrosurgical cutting mode, and the incidence rate for each adverse event was summarized. Results A total of 159 relevant articles were found; among them, 20 studies were included and 139 excluded. Five studies analyzed endoscopic papillectomy with the purecut/autocut mode and 16 with the blendcut/endocut mode. Only one study investigated both modes (purecut and endocut). With the purecut/autocut mode, the incidence of bleeding was 2.8-50%, and that of pancreatitis was 0-50% (mean: 12.8%). With the blendcut/endocut mode, the incidence of bleeding was 0-42.3%, and that of pancreatitis was 0%-17.9% (mean: 9.5%). Conclusion Both methods had high adverse event rates for endoscopic papillectomy. Thus, a standard method of endoscopic papillectomy, including the electrosurgical cutting mode, needs to be established.

Pancreatic cancer is the most lethal solid malignancy, and the number of patients with pancreatic cancer is increasing. Systemic chemotherapies are often ineffective for such patients, and there is an urgent need for personalized medicine. Unlike other types of cancer, personalized treatments for pancreatic cancer are still in development. Consequently, pancreatic cancer is less sensitive to anticancer drugs and is often refractory to common treatments. Therefore, advances in personalized medicine for pancreatic cancer are necessary. This review examined advances in personalized medicine for pancreatic cancer, including the use of endoscopic ultrasound (EUS)-guided sampling. EUS-guided sampling is widely used for diagnosing pancreatic tumors and is expected to be applied to sampled tissues. Additionally, there has been an increase in clinical research using EUS-guided sampling. The combination of precision medicine using genomic testing and pharmacological profiles based on high-throughput drug sensitivity testing using patient-derived organoids is expected to revolutionize pancreatic cancer treatment.