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Intraductal papillary mucinous carcinoma (IPMC) arising from the heterotopic pancreas is rare. A case of IPMC metastasis from the jejunal heterotopic pancreas was described. The heterotopic pancreas could be the source of the submucosal tumor-like lesion found in the small intestine with an elevated carbohydrate antigen (CA) 19-9 level. A 60-year-old woman was admitted to the hospital with pulmonary thromboembolism and anemia. The level of CA19-9, a tumor marker, was found to be 211.8U/ml. A tumor in the jejunum was discovered using contrast-enhanced computed tomography. There were also a number of hepatic tumors found. A submucosal tumor-like lesion in the jejunum was discovered during an enteroscopy, and a biopsy revealed it to be an adenocarcinoma. Partial resection of the jejunum was performed to control hemorrhage. Histopathology revealed an invasive IPMC arising from a heterotopic pancreas (Heinrich type II) and chemotherapy with gemcitabine and nab-paclitaxel was initiated. There have only been three cases of invasive IPMC from a heterotopic pancreas reported, and this is the first one to include chemotherapeutic treatment of distant metastasis.

A 58-year-old man was referred for obstructive jaundice. Imaging modalities revealed the presence of multiple pancreatic tumors and the stenosis of the middle common bile duct due to a hypoenhanced localized tumor. The multiple pancreatic tumors were histopathologically diagnosed as autoimmune pancreatitis by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). To differentiate between IgG4-related sclerosing cholangitis (IgG4-SC) and cholangiocarcinoma, we diagnosed the biliary tumor as IgG4-SC by EUS-FNA because of insufficient pathological materials obtained in a transpapillary manner. We herein report a case of IgG4-SC diagnosed by EUS-FNA.

The activation of the Kelch-like ECH-associated protein 1 (Keap1)-NF-E2-related factor 2 (Nrf2) pathway contributes to cancer progression in addition to oxidative stress responses. Loss-of-function Keap1 mutations were reported to activate Nrf2, leading to cancer progression. We examined the effects of Keap1 deletion in a cholangiocarcinoma mouse model using a mutant K-ras/ p53 mouse. Introduction of the Keap1 deletion into liver-specific mutant K-ras/ p53 expression resulted in the formation of invasive cholangiocarcinoma. Comprehensive analyses of the gene expression profiles identified broad upregulation of Nrf2-target genes such as Nqo1 and Gstm1 in the Keap1-deleted mutant K-ras/ p53 expressing livers, accompanied by upregulation of cholangiocyte-related genes. Among these genes, the transcriptional factor Sox9 was highly expressed in the dysplastic bile duct. The Keap-Nrf2-Sox9 axis might serve as a novel therapeutic target for cholangiocarcinoma. NEW & NOTEWORTHY The Keap1-Nrf2 system has a wide variety of effects in addition to the oxidative stress response in cancer cells. Addition of the liver-specific Keap1 deletion to mice harboring mutant K-ras and p53 accelerated cholangiocarcinoma formation, together with the hallmarks of Nrf2 activation. This process involved the expansion of Sox9-positive cells, indicating increased differentiation toward the cholangiocyte phenotype.

Chronic pancreatitis (CP) is a fibro-inflammatory disease of the pancreas. Early diagnosis and intervention, before CP becomes established and irreversible, are essential to improve the long-term outcomes. The world’s first diagnostic criteria for early CP were proposed in Japan in 2009, but their clinical utility remains elusive. This study aimed to clarify whether patients with early CP progress to definite CP. This is a multicenter, prospective study. Patients diagnosed as having early CP according to the Japanese diagnostic criteria were prospectively followed for 2 years. Clinical profiles including symptoms, drinking and smoking status, laboratory data, imaging findings and treatments were analyzed. Among the 83 patients who completed the 2-year follow-up period, four (4.8%) patients progressed to definite CP. The diagnosis of 48 (57.8%) patients was unchanged, and that of 31 (37.3%) patients was downgraded. All the four progressive patients were male, alcohol-related, smokers (3 current and 1 ever), and continued drinking. Comparison of the clinical profiles between the progression group (n = 4) and non-progression group (n = 79) revealed that etiology (alcohol-related), smoking status and presence of acute pancreatitis episodes were associated with the progression to definite CP. The Japanese diagnostic criteria could identify some patients before the progression to definite CP, while the majority of the patients did not progress. Trial registration number: UMIN000015992.

In patients with malignant perihilar biliary strictures, preoperative biliary drainage (PBD) of the hepatic lobe to be resected may decrease the liver volume of the future liver remnant (FLR) after percutaneous transhepatic portal vein embolization (PVE). However, evidence of its application is insufficient. This study aimed to clarify the effects of PBD on liver hypertrophy after PVE. Between January 2008 and December 2017, 169 patients with malignant perihilar biliary strictures underwent major hepatectomy or palliative surgery at our hospital. Of these, 76 patients who underwent PVE were categorized into two groups: group A (n = 29) who received unilateral PBD of the FLR and group B (n = 47) who received bilateral PBD, including that of the hepatic lobe to be resected. FLR ratios after PVE and liver hypertrophy ratios were retrospectively compared in both groups. Group B exhibited significantly severe biliary stenosis (p = 0.0038) and high serum bilirubin before biliary drainage (p = 0.0037). After PVE, the total liver volumes were 1287 ± 260 ml and 1340 ± 257 ml (p = 0.39), respectively. FLR volumes were 555 ± 135 and 577 ± 113 ml (p = 0.45), respectively. FLR ratios were 43.4 ± 8.2% and 43.4 ± 6.4%, respectively (p = 0.98). Liver hypertrophy ratios were 124.2 ± 17.7% and 129.2 ± 20.9%, respectively (p = 0.28). In addition, an examination which excluded patients with Bismuth type I obtained similar result. PBD of the hepatic lobe to be resected did not decrease the FLR ratios and hypertrophy ratios. Thus, in patients with poor biliary drainage, additional PBD of the target lobe is acceptable.

A 79-year-old woman was referred for pancreatic tail cancer with multiple liver metastases. The pancreatic tail tumor was diagnosed as acinar cell carcinoma (ACC) histologically by endoscopic ultrasound-guided fine-needle aspiration. Because of multiple liver metastases, S-1 chemotherapy was administered, resulting in a partial response to chemotherapy one year later. After approximately three years, liver atrophy and esophageal varices developed. We suspected S-1 as the cause of the liver cirrhosis. S-1 cessation minimized ascites and improved the esophageal varices. Although S-1 can potentially treat ACC, we should be watchful for liver cirrhosis caused by its long-term administration.

The interaction between pancreatic cancer cells and pancreatic stellate cells plays a pivotal role in the progression of pancreatic cancer. Pyruvate kinase isozyme M2 is a key enzyme in glycolysis. Previous studies have shown that pyruvate kinase isozyme M2 is overexpressed in pancreatic cancer and that it regulates the aggressive behaviors of pancreatic cancer cells. To clarify the role of pyruvate kinase isozyme M2 in the interactions between pancreatic cancer cells and pancreatic stellate cells. Pyruvate kinase isozyme M2-knockdown pancreatic cancer cells (Panc-1 and SUIT-2 cells) and pancreatic stellate cells were generated by the introduction of small interfering RNA-expressing vector against pyruvate kinase isozyme M2. Cell proliferation, migration, and epithelial–mesenchymal transition were examined in vitro. The impact of pyruvate kinase isozyme M2 knockdown on the growth of subcutaneous tumors was examined in nude mice in vivo. Pyruvate kinase isozyme M2-kockdown pancreatic cancer cells and pancreatic stellate cells showed decreased proliferation and migration compared to their respective control cells. Pancreatic stellate cell-induced proliferation, migration, and epithelial–mesenchymal transition were inhibited when pyruvate kinase isozyme M2 expression was knocked down in pancreatic cancer cells. In vivo, co-injection of pancreatic stellate cells increased the size of the tumor developed by the control SUIT-2 cells, but the effects were less evident when pyruvate kinase isozyme M2 was knocked down in SUIT-2 cells or pancreatic stellate cells. Our results suggested a critical role of pyruvate kinase isozyme M2 in the interaction between pancreatic cancer cells and pancreatic stellate cells.

The Kelch-like ECH-associated protein 1 (Keap1)-NF-E2-related factor 2 (Nrf2) system has a wide variety of effects in addition to the oxidative stress response, such as growth promotion and chemoresistance of cancer cells. Nrf2 is constitutively activated in most cancer cells. However, the activation of Nrf2 together with oncogenic mutations does not always result in cancer promotion. K-rasLSL-G12D/+:: p53LSL-R172H/+:: Pdx-1-Cre (KPC) mice are an established model of pancreatic cancer that specifically express mutants of both K-ras and p53 in the pancreas by using Pdx-1-Cre. We here generated Pdx-1-Cre::K-rasLSL-G12D/+:: Keap1fl/fl (KC::Keap1) and KPC:: Keap1fl/fl (KPC::Keap1) mice in which Nrf2 is constitutively activated by Keap1 deletion. KC::Keap1 and KPC::Keap1 mice started to die or showed obvious weakness at approximately around 40 days after birth. Histological examination revealed that KC::Keap1 and KPC::Keap1 mice did not develop pancreatic cancer but, instead, progressive atrophy of the pancreatic parenchyma. In these mice, amylase-positive acinar cells as well as insulin- and glucagon-positive islet cells were decreased and surrounded by fibrotic tissues. KC::Keap1 and KPC::Keap1 mice presented lower body weight and glucose levels than C::Keap1 mice, presumably resulting from pancreatic exocrine insufficiency. Histological changes were not obvious in C::Keap1 and PC::Keap1 mice. The presence of the p53 mutation did not affect the phenotypes in KC::Keap1 mice. Heterologous or homologous Nrf2 deletion ( Nrf2+/− or Nrf2−/−) rescued the pancreatic phenotypes, weight loss, and hypoglycemia in KC::Keap1 mice, suggesting that Nrf2 is a major downstream target of Keap1. In conclusion, simultaneous K-ras activation and Keap1 deletion caused progressive atrophy of the pancreatic parenchyma in mice. NEW & NOTEWORTHY Aberrant activation of the Kelch-like ECH-associated protein 1 (Keap1)-NF-E2-related factor 2 (Nrf2) system usually promotes carcinogenesis, and we assumed that simultaneous activation of K-ras and Nrf2 might promote pancreatic carcinogenesis. Conditional expression of mutant K-ras and Keap1 deletion did not result in pancreatic cancer development. Instead, these mice developed progressive loss of pancreatic parenchyma, accompanied by body weight loss and hypoglycemia, presumably because of pancreatic exocrine insufficiency. Nrf2 activation by Keap1 deletion concomitant with K-ras activation cause pancreatic atrophy.

Pancreaticojejunostomy stricture (PJS) is a late complication of pancreaticoduodenectomy. The endoscopic treatment of PJS is very challenging due to the difficulty of locating the small anastomotic site and passing the stricture using a guidewire. We herein report two cases of severe PJS. These patients could not be treated using only double-balloon endoscopy or endoscopic ultrasound-guided puncture of the main pancreatic duct because of severe stenosis at the anastomotic site. However, we could treat them by the rendezvous technique using the rigid part of the guidewire to penetrate PJS. This method was useful and safe for treating severe PJS.

The world’s first diagnostic criteria for early CP were proposed in 2009 in Japan. This study aimed to clarify the clinico-epidemiological features of early CP in Japan. Patients with early CP who were diagnosed according to the diagnostic criteria for early CP and had visited the selected hospitals in 2011 were surveyed. The study consisted of two-stage surveys: the number of patients with early CP was estimated by the first questionnaire and their clinical features were assessed by the second questionnaire. The estimated number of early CP patients was 5410 (95% confidence interval 3675–6945), with an overall prevalence of 4.2 per 100,000 persons. The number of patients who were newly diagnosed with early CP was estimated to be 1330 (95% confidence interval 1058–1602), with an annual incidence of 1.0 per 100,000 persons. Detailed clinical information was obtained in 151 patients in the second survey. The male-to-female sex ratio was 1.32:1. The mean age was 60.4 and the mean age at disease onset was 55.4. Idiopathic (47.7%) and alcoholic (45.0%) were the two most common etiologies. Proportions of female and idiopathic cases were higher in early CP than in definite CP. Hyperechoic foci without shadowing and stranding were the most common findings on endoscopic ultrasonography. The clinical profiles of early CP patients who showed lobularity with honeycombing on endoscopic ultrasonography or previous episodes of acute pancreatitis were similar to those of definite CP patients. We clarified the current status of early CP in Japan.

Host-derived factors alter gut microenvironment, and changes in gut microbiota also affect biological functions of host. Alterations of gut microbiota have been reported in a wide variety of diseases, but the whole picture of alterations in pancreatic diseases remains to be clarified. In particular, the gut microbiota may be affected by malnutrition or impaired exocrine pancreas function that is associated with pancreatic diseases. We here conducted comprehensive analysis of gut microbiota in patients with type 1 autoimmune pancreatitis (AIP), a pancreatic manifestation of the systemic IgG4-related disease, and chronic pancreatitis (CP). The two diseases were selected, because altered immune reactions in AIP and/or long-standing malnutrition in CP may influence the gut microbiota. Fecal samples were obtained from 12 patients with AIP before the steroid therapy and 8 patients with CP. Metagenome DNA was extracted, and microbiota was analyzed by next generation sequencing. Gut microbiota profiles were different between patients with AIP and those with CP; namely, the proportions of Bacteroides, Streptococcus and Clostridium species were higher in patients with CP. The reasons for the increased proportion of these bacterial species remain unknown, but may reflect malabsorption and/or decreased pancreatic enzymes, both of which are associated with CP. Incidentally, the identified Streptococcus species are oral cavity inhabitants and also known as pathogens for endocarditis. Despite the small sample size, this study has shown the differences in gut microbiota profiles between AIP and CP. Comprehensive analysis of the gut microbiota may be useful for the differential diagnosis of pancreatic diseases.

Pancreatic cancer cells (PCCs) interact with pancreatic stellate cells (PSCs), which play a pivotal role in pancreatic fibrogenesis, to develop the cancer-conditioned tumor microenvironment. Exosomes are membrane-enclosed nanovesicles, and have been increasingly recognized as important mediators of cell-to-cell communications. The aim of this study was to clarify the effects of PCC-derived exosomes on cell functions in PSCs. Exosomes were isolated from the conditioned medium of Panc-1 and SUIT-2 PCCs. Human primary PSCs were treated with PCC-derived exosomes. PCC-derived exosomes stimulated the proliferation, migration, activation of ERK and Akt, the mRNA expression of α-smooth muscle actin (ACTA2) and fibrosis-related genes, and procollagen type I C-peptide production in PSCs. Ingenuity pathway analysis of the microarray data identified transforming growth factor β1 and tumor necrosis factor as top upstream regulators. PCCs increased the expression of miR-1246 and miR-1290, abundantly contained in PCC-derived exosomes, in PSCs. Overexpression of miR-1290 induced the expression of ACTA2 and fibrosis-related genes in PSCs. In conclusion, PCC-derived exosomes stimulate activation and profibrogenic activities in PSCs. Exosome-mediated interactions between PSCs and PCCs might play a role in the development of the tumor microenvironment.