Feasibility of comprehensive genomic profiling using endoscopic ultrasound-guided tissue acquisition with a 22-gauge Franseen needle.

Aim: Comprehensive genomic profiling (CGP) test for solid tumors is now increasingly utilized in clinical practice, especially in pancreatobiliary cancer, and specimens obtained by endoscopic ultrasound-guided tissue acquisition (EUS-TA) are often submitted for tissue-based CGP test. In this study, we evaluated the feasibility of EUS-TA using a 22-gauge Franseen needle for the CGP test. Methods: Consecutive patients with solid tumors who underwent EUS-TA using a 22-gauge Franseen needle, and whose tissue samples were pre-checked for suitability for CGP test, were included in this single-center, retrospective analysis. The success rates of appropriate sample collection for CGP evaluated by pathologists (1st quality control) and CGP test (2nd quality control) were evaluated. In addition, The EUS-TA slides were evaluated for the tissue area and tumor area content, using the image software. Results: A total of 50 cases, with 78% of pancreatic cancer, were included in the analysis. A median of 3 passes of EUS-TA were performed with an adverse event rate of 4%. The success rates for 1st and 2nd quality control for CGP tests were 86% and 76%, respectively. The image analyses suggested EUS-TA specimen did not always fulfill CGP test criteria, with 18% of tissue area ≥16 mm2 and 38% of tumor area content ≥20%, even in cases with successful CGP tests. The suction method yielded a significantly larger amount of DNA but without a significant difference in the multivariate analysis. Conclusions: The present study demonstrated the feasibility of EUS-TA using a 22-gauge Franseen needle for CGP test.

Intraductal Papillary Mucinous Neoplasm Surveillance Leads to Early Diagnosis and Better Outcomes of Concomitant Cancer.

OBJECTIVE: To examine whether long-term surveillance of intraductal papillary mucinous neoplasms (IPMNs) leads to early diagnosis and better clinical outcomes of pancreatic ductal adenocarcinomas (PDACs) developing concomitantly with IPMNs. SUMMARY BACKGROUND DATA: Long-term image-based surveillance is recommended for patients with low-risk IPMNs. However, it is unknown whether the surveillance can improve surgical and survival outcomes of patients with concomitant PDACs. METHODS: Using a prospective single-institutional cohort of 4,620 patients with pancreatic cysts including 3,638 IPMN patients, we identified 63 patients who developed concomitant PDAC during long-term surveillance. We compared overall survival (OS) of 46 cases with concomitant PDAC to that of 460 matched cases diagnosed with non-IPMN-associated PDAC at the same institution. Multivariable hazard ratios and 95% confidence intervals (CIs) for overall mortality were computed using the Cox regression model with adjustment for potential confounders. RESULTS: Concomitant PDACs were identified at an earlier cancer stage compared to non-IPMN-associated PDACs with 67% and 38% cases identified at stage 2 or earlier, respectively (P<0.001) and 57% and 21% cases with R0 resection, respectively (P<0.001). Compared to non-IPMN-associated PDACs, concomitant PDACs were associated with longer OS (P=0.034) with a multivariable hazard ratio of 0.61 (95% CI, 0.39-0.96). The 5-year survival rate of patients with concomitant PDAC was higher compared to patients with non-IPMN-associated PDAC (34% vs. 18%, respectively; P=0.018). CONCLUSIONS: The surveillance for patients with IPMNs was associated with early identification of concomitant PDACs and longer survival of patients diagnosed with this malignancy.

Balloon endoscopy-assisted endoscopic retrograde cholangiopancreatography for hepatolithiasis in patients with hepaticojejunostomy.

BACKGROUND AND AIM: Balloon endoscopy-assisted endoscopic retrograde cholangiopancreatography (BE-ERCP) is an emerging procedure for pancreatobiliary diseases in patients with surgically altered anatomy. However, data on BE-ERCP for hepatolithiasis after hepaticojejunostomy (HJS) are still limited. METHODS: Stone removal success, adverse events and recurrence were retrospectively studied in consecutive patients who underwent BE-ERCP for hepatolithiasis after HJS between January 2011 and October 2022. Subgroup analysis was performed to compare clinical outcomes between patients who had undergone HJS over 10 years before (past HJS group) and within 10 years (recent HJS group). RESULTS: A total of 131 patients were included; 39% had undergone HJS for malignancy and 32% for congenital biliary dilation. Scope insertion and complete stone removal were successful in 89% and 73%, respectively. Early adverse events were observed in 9.9%. Four patients (3.1%) developed gastrointestinal perforation but could be managed conservatively. Hepatolithiasis recurrence rate was 17%, 20% and 31% in 1-year, 3-year, and 5-year after complete stone removal. The past HJS group was the only risk factor for failed stone removal (odds ratio 10.4, 95% confidence interval 2.99-36.5) in the multivariable analysis. Failed scope insertion (20%) and failed guidewire or device insertion to the bile duct (22%) were two major reasons for failed stone removal in the past HJS group. CONCLUSIONS: BE-ERCP for hepatolithiasis was effective and safe in cases with HJS but the complete stone removal rate was low in the past HJS group. Recurrent hepatolithiasis was common and careful follow up study is needed even after complete stone removal.

Skeletal muscle status and survival among patients with advanced biliary tract cancer.

BACKGROUND: Studies have demonstrated a prognostic role of sarcopenia (i.e., loss of skeletal muscle volume and functionality) in patients with various cancer types. In patients with biliary tract cancer, the quantity and quality of skeletal muscles and their serial changes have not been fully investigated in relation to survival outcomes. METHODS: We identified 386 patients with unresectable or recurrent biliary tract cancer and calculated skeletal muscle index (SMI) and skeletal muscle density (SMD) to estimate muscular quantity and quality, respectively, based on computed tomography images. Using the Cox regression model with adjustment for potential confounders, we calculated hazard ratios (HRs) and 95% confidence intervals (CIs) for progression-free survival (PFS) and overall survival (OS) according to skeletal muscle status and its serial change. RESULTS: Compared to patients without sarcopenia, patients with sarcopenia were associated with shorter PFS (multivariable HR, 1.60; 95% CI, 1.15-2.22; P = 0.005), but not with OS (P = 0.027) at the adjusted α level of 0.013. SMD at baseline was associated with OS (multivariable HR comparing the extreme quartiles, 1.52; 95% CI, 1.07-2.14; Ptrend = 0.012), but not with PFS (Ptrend = 0.13). A reduction in SMI rather than that in SMD was associated with OS. Progressive disease was a risk factor for reductions in SMI and SMD. CONCLUSIONS: Skeletal muscle quantity and quality and their serial changes were associated with survival outcomes in patients with advanced biliary tract cancer. Our data highlight the importance of designing nutritional and physical interventions for improvements in skeletal muscle status.

Satellite double-stranded RNA induces mesenchymal transition in pancreatic cancer by regulating alternative splicing.

Human satellite II (HSATII), composed of tandem repeats in pericentromeric regions, is aberrantly transcribed in epithelial cancers, particularly pancreatic cancer. Dysregulation of repetitive elements in cancer tissues can facilitate incidental dsRNA formation; however, it remains controversial whether dsRNAs play tumor-promoting or tumor-suppressing roles during cancer progression. Therefore, we focused on the double-stranded formation of HSATII RNA and explored its molecular function. The overexpression of double-stranded HSATII (dsHSATII) RNA promoted mesenchymal-like morphological changes and enhanced the invasiveness of pancreatic cancer cells. We identified an RNA-binding protein, spermatid perinuclear RNA-binding protein (STRBP), which preferentially binds to dsHSATII RNA rather than single-stranded HSATII RNA. The mesenchymal transition of dsHSATII-expressing cells was rescued by STRBP overexpression. Mechanistically, STRBP is involved in the alternative splicing of genes associated with epithelial-mesenchymal transition (EMT). We also confirmed that isoform switching of CLSTN1, driven by dsHSATII overexpression or STRBP depletion, induced EMT-like morphological changes. These findings reveal a novel tumor-promoting function of dsHSATII RNA, inducing EMT-like changes and cell invasiveness, thus enhancing our understanding of the biological significance of aberrant expression of satellite arrays in malignant tumors.

Retrospective comparative study of new slim-delivery and conventional large-cell stents for stent-in-stent methods for hilar malignant biliary obstruction.

OBJECTIVES: Endoscopic management of unresectable hilar malignant biliary obstruction (HMBO) is technically challenging, and effectiveness of stent-in-stent using large-cell, metal stents was reported. A new, large-cell stent with a 6F tapered delivery system was recently developed. The aim of this study was to compare clinical outcomes of slim-delivery and conventional large-cell stents. METHODS: This was a multicenter retrospective comparative study of stent-in-stent methods using slim-delivery stents (Niti-S Large Cell SR Slim Delivery [LC slim-delivery]) and conventional stents (Niti-S large-cell D-type; LCD) for unresectable HMBO. RESULTS: Eighty-three patients with HMBO were included; 31 LC slim-delivery and 52 LCD. Overall technical and clinical success rates were 100% and 90% in LC slim-delivery group and 98% and 88% in LCD group. Use of the LC slim-delivery was associated with shorter stent placement time in the multiple regression analysis, with a stent placement time of 18 and 23 min in LC slim-delivery and LCD groups, respectively. The early adverse event (AE) rate of LC slim-delivery was 10%, with no cholangitis or cholecystitis as compared to 23% in the LCD group. Recurrent biliary obstruction (RBO) rates and time to RBO were comparable between the two groups: 35% and 44%, and 8.5 and 8.0 months in LC slim-delivery and LCD groups, respectively. The major cause of RBO was tumor ingrowth (82%) in the LC slim-delivery group and sludge (43%) and ingrowth (48%) in LCD group. CONCLUSION: Stent-in-stent methods using LC slim-delivery shortened stent placement time with low early AE rates and comparable time to RBO in patients with HMBO.

Second Covered and Uncovered Self-Expandable Metal Stents for Recurrent Gastric Outlet Obstruction: A Retrospective Comparative Study.

Background: Endoscopic self-expandable metal stent (SEMS) placement is a current mainstay for malignant gastric outlet obstruction (GOO), but symptomatic recurrence due to initial SEMS dysfunction commonly occurs. We aimed to compare the safety and effectiveness of second SEMS for recurrent GOO (RGOO). Methods: Between April 2006 and December 2022, a total of 95 cases with malignant RGOO undergoing second endoscopic SEMS placement were enrolled. Technical and clinical success rates, RGOO, time to RGOO (TRGOO), stent patency rate, adverse events (AE), and overall survival (OS) were retrospectively compared between covered and uncovered SEMS (cSEMS/uSEMS) groups. Risk factors for TRGOO were also explored. Results: Baseline characteristics were well balanced between cSEMS (n = 48) and uSEMS (n = 47) groups, except for the causes of the initial SEMS dysfunction. High technical and clinical success rates with a similar incidence of AE (15% vs. 17%, p = 0.78) and OS (median of 101 vs. 102 days, p = 0.68) were achieved in both groups. There were no statistical differences in cumulative incidence of RGOO (19% vs. 13%, p = 0.58), TRGOO (median, not reached in both groups, p = 0.57), and stent patency rates at 1, 2, and 3 months between the groups (60%, 47% and 26%, respectively vs. 70%, 55% and 38%, respectively). However, TRGOO tended to be longer in cSEMS in cases with RGOO due to tumor ingrowth (median, not reached vs. 111 days, p = 0.19). A Cox regression analysis demonstrated that chemotherapy after second SEMS placement was significantly associated with an improved TRGOO (the hazard ratio of 0.27 [95% confidence interval, 0.08-0.93], p = 0.03). Conclusions: Regardless of the type of SEMS, second SEMS placement was similarly safe and effective for RGOO. The type of second SEMS might be considered based on the cause of initial SEMS dysfunction.

Clinical trajectory of intraductal papillary mucinous neoplasms progressing to pancreatic carcinomas during long-term surveillance: a prospective series of 100 carcinoma cases.

BACKGROUND: Trajectories of serological and morphological signatures have not been documented in pancreatic carcinogenesis related to intraductal papillary mucinous neoplasms (IPMNs). METHODS: Using a prospective cohort of 3437 IPMN patients, we identified 100 IPMN patients who developed pancreatic carcinomas during long-term surveillance. We examined serial changes of blood markers (carbohydrate antigen 19-9 [CA19-9], hemoglobin A1c [HbA1c], and pancreatic enzymes) and morphological features (worrisome features and high-risk stigmata) during the prediagnostic period of pancreatic carcinomas, overall and by carcinoma types (IPMN-derived vs. concomitant pancreatic carcinomas). RESULTS: CA19-9 elevation was observed in 39 patients and was associated with a metastatic stage. Compared to IPMN-derived carcinomas, concomitant carcinomas were more likely to represent CA19-9 elevation (60% vs. 30%, respectively; P = 0.005). HbA1c levels elevated only in 3 patients. Pancreatic enzyme elevation was observed in 18 patients with no differences in frequencies between the carcinoma types. All patients with elevated levels of blood markers had positive findings on cross-sectional imaging. High-risk stigmata or worrisome features were observed in all patients but one with concomitant carcinoma. The most common types of worrisome features were the main pancreatic duct dilatation and CA19-9 elevation in IPMN-derived and concomitant carcinomas, respectively. Compared to IPMN-derived carcinomas, concomitant carcinomas were less likely to harbor high-risk stigmata (16% vs. 86%, respectively; P < 0.001). CONCLUSIONS: The usefulness of currently available blood biomarkers was limited in early detection of pancreatic carcinomas related to IPMNs. Morphological alterations were well correlated with long-term risk of IPMN-derived carcinomas, but not with that of concomitant carcinomas.

Post-operative mortality and recurrence patterns in pancreatic cancer according to KRAS mutation and CDKN2A, p53, and SMAD4 expression.

Alterations in KRAS, CDKN2A (p16), TP53, and SMAD4 genes have been major drivers of pancreatic carcinogenesis. The clinical course of patients with pancreatic cancer in relation to these driver alterations has not been fully characterised in large populations. We hypothesised that pancreatic carcinomas with different combinations of KRAS mutation and aberrant expression of CDKN2A, p53, and SMAD4 might show distinctive recurrence patterns and post-operative survival outcomes. To test this hypothesis, we utilised a multi-institutional cohort of 1,146 resected pancreatic carcinomas and assessed KRAS mutations by droplet digital polymerase chain reaction and CDKN2A, p53, and SMAD4 expression by immunohistochemistry. Multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) for disease-free survival (DFS) and overall survival (OS) were computed according to each molecular alteration and the number of altered genes using the Cox regression models. Multivariable competing risks regression analyses were conducted to assess the associations of the number of altered genes with specific patterns of recurrence. Loss of SMAD4 expression was associated with short DFS (multivariable HR, 1.24; 95% CI, 1.09-1.43) and OS times (multivariable HR, 1.27; 95% CI, 1.10-1.46). Compared to cases with 0-2 altered genes, cases with three and four altered genes had multivariable HRs for OS of 1.28 (95% CI, 1.09-1.51) and 1.47 (95% CI, 1.22-1.78), respectively (ptrend < 0.001). Patients with an increasing number of altered genes were more likely to have short DFS time (ptrend = 0.003) and to develop liver metastasis (ptrend = 0.006) rather than recurrence at local or other distant sites. In conclusion, loss of SMAD4 expression and an increasing number of altered genes were associated with unfavourable outcomes in pancreatic cancer patients. This study suggests that the accumulation of the four major driver alterations can confer a high metastatic potential to the liver, thereby impairing post-operative survival among patients with pancreatic cancer.

Early skeletal muscle mass decline is a prognostic factor in patients receiving gemcitabine plus nab-paclitaxel for unresectable pancreatic cancer: a retrospective observational study.

PURPOSE: Patients with pancreatic cancer often have cancer cachexia at diagnosis. Recent studies suggested that loss of skeletal muscle mass was related to cancer cachexia, which hindered continuance of chemotherapy and could be one of prognostic factors in pancreatic cancer, however the association remains unclear in patients receiving gemcitabine and nab-paclitaxel (GnP). METHODS: We retrospectively studied 138 patients with unresectable pancreatic cancer receiving first-line GnP at the University of Tokyo from January 2015 to September 2020. We calculated body composition in CT images before chemotherapy and at initial evaluation, and evaluated the association of both body composition before chemotherapy and its changes at initial evaluation. RESULTS: Compared by skeletal muscle mass index (SMI) change rate between pre-chemotherapy and initial evaluation, there were statistically significantly differences in the median OS: 16.3 months (95%CI 12.3-22.7) and 10.3 months (95%CI 8.3-18.1) between SMI change rate ≥ -3.5% and < -3.5% groups (P = 0.01). By multivariate analysis for OS, CA19-9 (HR 3.34, 95%CI 2.00-5.57, P < 0.01), PLR (HR 1.68, 95%CI 1.01-2.78, P = 0.04), mGPS (HR 2.32, 95%CI 1.47-3.65, P < 0.01) and relative dose intensity (HR 2.21, 95%CI 1.42-3.46, P < 0.01) were significantly poor prognostic factors. SMI change rate (HR 1.47, 95%CI 0.95-2.28, P = 0.08) showed a trend to poor prognosis. Sarcopenia before chemotherapy was not significantly associated with PFS or OS. CONCLUSION: Early skeletal muscle mass decline was associated with poor OS. Further investigation is warranted whether the maintenance of skeletal muscle mass by nutritional support would improve prognosis.

Acute pancreatitis as the initial manifestation of acute myeloid leukemia with chromosome 16 rearrangements.

Acute pancreatitis is an acute inflammatory process of the pancreas that is becoming an increasingly common clinical issue. The most frequent underlying etiologies include gallstones and chronic alcohol use, which account for more than two-thirds of cases. We recently experienced a rare case of acute myeloid leukemia (AML) presenting with recurrent acute pancreatitis, which we later discovered was caused by diffusely infiltrating extramedullary sarcoma in the pancreas. Comprehensive analysis of previous cases of AML presenting as acute pancreatitis suggested involvement of cytogenetic alterations in chromosome 16 in its pathogenesis. Further improvement in management of acute pancreatitis is needed, and clinicians should note that this occasionally fatal condition can be the initial and only manifestation of AML. In practice, prompt initiation of intensive chemotherapy is critical for treating such cases of AML-induced acute pancreatitis.

Clinical Outcomes of Intraductal Papillary Mucinous Neoplasms With Dilatation of the Main Pancreatic Duct.

BACKGROUND & AIMS: Dilatation of the main pancreatic duct (MPD) has been a surgical indication for intraductal papillary mucinous neoplasms (IPMNs). Few studies have investigated long-term outcomes of IPMNs with MPD dilatation. METHODS: Among 3610 patients diagnosed with pancreatic cysts between 1994 and 2021, we identified 2829 IPMN patients, including 282 patients with MPD ≥5 mm, and examined short-term (≤6 months) and long-term risks of pancreatic carcinoma. Utilizing competing risks proportional hazards models, we estimated subdistribution hazard ratios for incidence of pancreatic carcinoma with adjustment for potential confounders. RESULTS: In analyses of short-term outcomes of the 282 patients with MPD dilatation, 72 (26%) patients were diagnosed with pancreatic carcinoma based on surgical or nonsurgical exploration. During long-term follow-up of 168 patients, we documented 24 (14%) patients diagnosed with pancreatic carcinoma (18 with IPMN-derived carcinoma and 6 with concomitant ductal adenocarcinoma). The patients with the MPD = 5-9.9 mm had cumulative incidence rates of pancreatic carcinoma diagnosis of 8.1% (95% confidence interval [CI], 4.3%-13.5%) and 10.0% (95% CI, 5.5%-15.9%) at 2 and 5 years, respectively; and the patients with the MPD ≥10 mm had the corresponding rates of 16.0% (95% CI, 3.6-36.5%) and 33.3% (95% CI, 10.3%-58.8%). The multivariable subdistribution hazard ratios were 2.78 (95% CI, 1.57-4.90) and 7.00 (95% CI, 2.58-19.0) for the MPD = 5-9.9 mm and ≥10 mm (vs <5 mm), respectively. CONCLUSIONS: IPMNs with MPD dilatation at baseline were associated with higher prevalence and incidence of pancreatic carcinoma compared with IPMNs with no MPD dilatation.

Combination of serum human satellite RNA and miR-21-5p levels as a biomarker for pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis due to the difficulty of its diagnosis. Because human satellite II (HSATII) RNA, a satellite repeat RNA, is highly and specifically expressed in human PDAC, the serum HSATII RNA level may be a biomarker of PDAC. To measure the serum HSATII RNA level with high sensitivity and reproducibility, we previously developed a convenient method, tandem repeat amplification by nuclease protection (TRAP) combined with droplet digital PCR (ddPCR). Here, we refined the original method by simultaneously measuring the serum miR-21-5p level to enhance the detection of PDAC. The resulting PDAC-Index, constructed using serum HSATII RNA and miR-21-5p levels, discriminated patients with PDAC with high accuracy. We verified the clinical usefulness of the PDAC-Index as a supportive test in difficult-to-diagnose cases. The PDAC-Index has satisfactory diagnostic performance and may routinely be applied for detecting PDAC.

Endoscopic Bridge-and-Seal of Bile Leaks Using a Fully Covered Self-Expandable Metallic Stent above the Papilla.

BACKGROUND/AIMS: Endoscopic management by endoscopic sphincterotomy with or without plastic stents or fully covered self-expandable metallic stents (FCSEMSs) is widely accepted as the current standard of care for postoperative bile leaks. Biliary stents are placed across the papilla, not above the papilla. We investigated the safety and effectiveness of the bridge-and-seal technique for bile leaks by the placement of FCSEMS above the papilla. METHODS: This was a retrospective study of FCSEMS placement above the papilla for bile leaks between October 2016 and July 2021. FCSEMS was placed above the papilla to bridge and seal the leak. The main outcome measures were the resolution of bile leaks and adverse events. RESULTS: Seven patients with postoperative bile leaks underwent FCSEMS above the papilla. The locations of bile leaks were 1 cystic duct remnant; 2 intrahepatic bile duct; 1 hepatic duct; 2 common bile duct and 1 anastomosis. The technical success rate of FCSEMS placement was 100%, and resolution of bile leaks was achieved in five patients (71.4%). All the adverse events were observed after FCSEMS removal; as follows: 1 moderate cholangitis; 2 mild post-ERCP pancreatitis; and 1 mild remnant cholecystitis. CONCLUSIONS: FCSEMS placement above the papilla can be a treatment option for postoperative bile leaks.

KRAS variant allele frequency, but not mutation positivity, associates with survival of patients with pancreatic cancer.

KRAS mutation is a major driver of pancreatic carcinogenesis and will likely be a therapeutic target. Due to lack of sensitive assays for clinical samples of pancreatic cancer with low cellularity, KRAS mutations and their prognostic association have not been fully examined in large populations. In a multi-institutional cohort of 1162 pancreatic cancer patients with formalin-fixed paraffin-embedded tumor samples, we undertook droplet digital PCR (ddPCR) for KRAS codons 12/13/61. We examined detection rates of KRAS mutations by clinicopathological parameters and survival associations of KRAS mutation status. Multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) for disease-free survival (DFS) and overall survival (OS) were computed using the Cox regression model with adjustment for potential confounders. KRAS mutations were detected in 1139 (98%) patients. The detection rate did not differ by age of tissue blocks, tumor cellularity, or receipt of neoadjuvant chemotherapy. KRAS mutations were not associated with DFS or OS (multivariable HR comparing KRAS-mutant to KRAS-wild-type tumors, 1.04 [95% CI, 0.62-1.75] and 1.05 [95% CI, 0.60-1.84], respectively). Among KRAS-mutant tumors, KRAS variant allele frequency (VAF) was inversely associated with DFS and OS with HRs per 20% VAF increase of 1.27 (95% CI, 1.13-1.42; ptrend <0.001) and 1.31 (95% CI, 1.16-1.48; ptrend <0.001), respectively. In summary, ddPCR detected KRAS mutations in clinical specimens of pancreatic cancer with high sensitivity irrespective of parameters potentially affecting mutation detections. KRAS VAF, but not mutation positivity, was associated with survival of pancreatic cancer patients.

Intra-abdominal hemorrhage as a rare complication of endoscopic ultrasonography: A case report.

Intra-abdominal hemorrhage after endoscopic ultrasonography (EUS) is an uncommon complication, which can lead to potentially fatal outcomes. We describe a case of intra-abdominal hemorrhage due to left gastric arterial bleeding after EUS. The patient developed severe epigastric pain 10 h after diagnostic EUS for pancreatic cysts. Contrast-enhanced computed tomography revealed extravasation from the left gastric artery as well as a hematoma in the lesser omentum, which was confirmed by emergent angiography. Spontaneous hemostasis was obtained without embolization and the patient did not have further episodes of intra-abdominal hemorrhage. Endoscopists should be aware of this rare but serious complication after endoscopic procedures.

Mutant KRAS drives metabolic reprogramming and autophagic flux in premalignant pancreatic cells.

Mutational activation of the KRAS gene occurs in almost all pancreatic ductal adenocarcinoma (PDAC) and is the earliest molecular event in their carcinogenesis. Evidence has accumulated of the metabolic reprogramming in PDAC, such as amino acid homeostasis and autophagic flux. However, the biological effects of KRAS mutation on metabolic reprogramming at the earlier stages of PDAC carcinogenesis are unclear. Here we report dynamic metabolic reprogramming in immortalized human non-cancerous pancreatic ductal epithelial cells, in which a KRAS mutation was induced by gene-editing, which may mimic early pancreatic carcinogenesis. Similar to the cases of PDAC, KRAS gene mutation increased the dependency on glucose and glutamine for maintaining the intracellular redox balance. In addition, the intracellular levels of amino acids were significantly decreased because of active protein synthesis, and the cells required greater autophagic flux to maintain their viability. The lysosomal inhibitor chloroquine significantly inhibited cell proliferation. Therefore, metabolic reprogramming is an early event in carcinogenesis initiated by KRAS gene mutation, suggesting a rationale for the development of nutritional interventions that suppress or delay the development of PDAC.

MNX1-HNF1B Axis Is Indispensable for Intraductal Papillary Mucinous Neoplasm Lineages.

BACKGROUND & AIMS: Chromatin architecture governs cell lineages by regulating the specific gene expression; however, its role in the diversity of cancer development remains unknown. Among pancreatic cancers, pancreatic ductal adenocarcinoma (PDAC) and intraductal papillary mucinous neoplasms (IPMN) with an associated invasive carcinoma (IPMNinv) arise from 2 distinct precursors, and their fundamental differences remain obscure. Here, we aimed to assess the difference of chromatin architecture regulating the transcriptional signatures or biological features in pancreatic cancers. METHODS: We established 28 human organoids from distinct subtypes of pancreatic tumors, including IPMN, IPMNinv, and PDAC. We performed exome sequencing (seq), RNA-seq, assay for transposase-accessible chromatin-seq, chromatin immunoprecipitation-seq, high-throughput chromosome conformation capture, and phenotypic analyses with short hairpin RNA or clustered regularly interspaced short palindromic repeats interference. RESULTS: Established organoids successfully reproduced the histology of primary tumors. IPMN and IPMNinv organoids harbored GNAS, RNF43, or KLF4 mutations and showed the distinct expression profiles compared with PDAC. Chromatin accessibility profiles revealed the gain of stomach-specific open regions in IPMN and the pattern of diverse gastrointestinal tissues in IPMNinv. In contrast, PDAC presented an impressive loss of accessible regions compared with normal pancreatic ducts. Transcription factor footprint analysis and functional assays identified that MNX1 and HNF1B were biologically indispensable for IPMN lineages. The upregulation of MNX1 was specifically marked in the human IPMN lineage tissues. The MNX1-HNF1B axis governed a set of genes, including MYC, SOX9, and OLFM4, which are known to be essential for gastrointestinal stem cells. High-throughput chromosome conformation capture analysis suggested the HNF1B target genes to be 3-dimensionally connected in the genome of IPMNinv. CONCLUSIONS: Our organoid analyses identified the MNX1-HNF1B axis to be biologically significant in IPMN lineages.

Emerging Roles of Exosomal Circular RNAs in Cancer.

Circular RNA (circRNA) is a type of non-coding RNA that forms a covalently closed continuous loop. The expression pattern of circRNA varies among cell types and tissues, and many circRNAs are aberrantly expressed in various cancers. Aberrantly expressed circRNAs have been shown to play crucial roles in carcinogenesis, functioning as microRNA sponges or new templates for protein translation. Recent research has shown that circRNAs are enriched in exosomes. Exosomes are secretory vesicles that mediate intercellular communication through the delivery of cargo, including proteins, lipids, DNA, and RNA. Exosome-mediated crosstalk between cancer cells and the tumor microenvironment promotes the epithelial-mesenchymal transition, angiogenesis, and immune escape, and thus may contribute to cancer invasion and metastasis. In this review, we discuss the biological functions of exosomal circRNAs and their significance in cancer progression. Additionally, we discuss the potential clinical applications of exosomal circRNAs as biomarkers and in cancer therapy.

Endoscopic Ultrasound-Guided Tissue Acquisition by 22-Gauge Franseen and Standard Needles for Solid Pancreatic Lesions.

Background/Aims: Recently, a three-plane symmetric needle with Franseen geometry was developed for endoscopic ultrasound-guided fine needle biopsy (EUS-FNB). In this retrospective study, tissue acquisition per pass was compared between 22-gauge Franseen FNB and standard fine needle aspiration (FNA) needles in patients with solid pancreatic lesions. Methods: Consecutive patients who underwent EUSFNA or EUS-FNB for solid pancreatic lesions between October 2014 and March 2018 were retrospectively studied. The tissue acquisition rate and the diagnostic performance per session, per pass, and at first pass were compared. Results: A total of 663 passes (300 by the FNB needle and 363 by the standard FNA needle) were performed in 154 patients (71 FNB and 83 FNA). The tissue acquisition rate per session and at first pass in the FNB and FNA groups was 100% and 95% (p=0.13) and 87% and 69% (p=0.007), respectively. The multivariate analysis revealed that among the patients, EUS-FNB (odds ratio, 3.07; p=0.01) was associated with a higher first-pass tissue acquisition rate. While the tissue acquisition rate reached a plateau after the 4th pass with FNA, it reached a plateau after the 2nd pass with FNB. Among the 129 malignant cases, the histological tissue acquisition rate per session was similar (100% and 94%), but the sensitivity by histology alone per session was higher for FNB than for FNA (93% and 73%, p<0.01). Conclusions: The results of our retrospective analysis indicated that compared with a standard FNA needle, a 22-gauge Franseen FNB needle was associated with a higher first-pass tissue acquisition rate.