Pancreatic cancer is a highly lethal cancer type. The genomic landscape of the pancreatic cancer genome features four frequently mutated genes (KRAS, CDKN2A/p16, TP53 and SMAD4/DPC4) and dozens of candidate driver genes altered at low frequency, including potential clinical targets. Molecular profiling of tumor specimens has revealed potential targets for personalized anticancer therapy and seen a shift toward an emerging molecular taxonomy of cancer. We are increasingly becoming aware of the problem of intra-tumor heterogeneity. Intra-tumor heterogeneity poses a challenge to personalized cancer medicine because a single needle biopsy or surgical excision is unlikely to accurately capture the complete genomic landscape of a patient's cancer. Furthermore, studies for molecular screening often exclude some patients because of inability to obtain a biopsy, insufficient or no tumor content in the available specimen, or deteriorating performance status. The presence of tumor-derived DNA in circulating cell-free DNA provides a less-invasive approach to diagnose cancers, monitor chemotherapy-resistant mutations and overcome the problem of tumor heterogeneity. Genomic characterization of cell-free circulating tumor DNA may offer an opportunity to assess clonal dynamics throughout the course of a patient's illness and identify drivers of therapeutic resistance. As technology advances, it may be possible to perform targeted molecular analysis using "liquid clinical sequencing" using circulating cell-free DNA. This approach could solve many of the problems that we have encountered in obtaining tumor tissue. Significant efforts are under way to explore these approaches for "Precision Medicine".

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Intracellular activation of trypsinogen was considered to be the key mechanism responsible for the initiation of acute pancreatitis. However, accumulating evidence has suggested that activation of trypsinogen, activation of NF-κB, impairment of autophagy, oxidative stress, ER stress, and derangement in calcium signaling occur simultaneously in the onset of acute pancreatitis. The precise mechanism of acute pancreatitis is still obscure and there is no specific treatment. The exocrine secretion of pancreatic enzymes is regulated by cytoplasmic calcium concentration ([Ca²⁺]i). The signals of acetylcholine and cholecystokinin through their receptors, localized on the basal plasma membrane, induce a calcium spike in the apical area of the acinar cell, resulting in the secretion of pancreatic enzymes. Pathological signals by hyperstimulation of secretagogue, bile and alcohol metabolites, cause sustained and global [Ca²⁺]i elevation, followed by trypsinogen activation, vacuolization and necrosis, all of which are crucial in the development of pancreatitis. When we inhibited such a prolonged and abnormal [Ca²⁺]i elevation using calcium sensor (calmodulin), specific Ca²⁺ chelator, and CRAC channel blocker, premature enzyme activation, vacuole formation and acinar cell damage were reduced. In this section, physiological and pathological calcium signaling and the onset of acute pancreatitis are discussed.

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Glycosylation, -a common post-translational modification of proteins,- is involved in several processes associated with cancer progression, including signaling, cell-cell adhesion, invasion and metastasis. We previously found that levels of multi-branch antennary and fucosylated glycans were elevated in pancreatic cancer and hepatocellular carcinoma. Another potentially malignant disorder of the pancreas, invasive pancreatic intraductal papillary mucinous neoplasm (IPMN), is hard to diagnose pre-operatively. A new serum biomarker for invasive IPMNs would help to diagnosis and identify cases needing high-risk pancreatic resection. In our recent study, we evaluated the potential use of glycans as clinical markers for invasive IPMNs. N-glycan profiles of whole-serum samples were evaluated from patients with a confirmed diagnosis of IPMNs. The serum profiles showed high expression levels of fucosylated glycans with multi-branch antennary structures, suggesting that these complex glycans may serve as biomarkers for the prediction of invasive IPMNs.

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Recently, long non-coding RNAs (lncRNAs), which are defined as non-coding RNAs (ncRNA) of more than 200 nucleotides in length, are being increasingly revealed to contribute to various biological processes in several diseases including cancer via diverse mechanisms. It has been reported that some lncRNAs can be transferred by extracellular vesicle (EV) from donor cells to recipient cells, and modulate cell signaling and behaviors in the recipient cells. Although the roles of EV lncRNAs on carcinogenesis or the development of pancreatic cancer were not well understood, several lncRNAs have been associated with playing important regulatory roles in epithelial-mesenchymal transition (EMT), which regulates invasion and metastasis in pancreatic cancer. Therefore, to investigate the roles of lncRNA and the mechanisms of lncRNA transfer by EV, would provide several useful insights to improve the clinical applications for diagnosis and therapy in human pancreatic cancer.

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Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease and there is a compelling need for the elucidation of molecular mechanisms underlying invasion and metastasis. To improve therapeutic targets, we have previously identified the homeobox transcription factor Prrx1 as an overlapped key molecule in pancreatic development, regeneration and early carcinogenesis. Here, we demonstrate the differential biological roles of Prrx1a and Prrx1b in PDAC progression. In in vitro experiments, Prrx1a and Prrx1b are highly expressed in metastatic liver cells of PDAC and primary PDAC cells, respectively. Prrx1b overexpression in PDAC cells associates with epithelial-mesenchymal transition (EMT) and promotes invasion. Ficlatuzumab, a neutralizing antibody against Hgf which is a downstream target of Prrx1b, significantly inhibits cancer cell invasion. We also found that the combination of gemcitabine and ficlatuzumab, significantly reduced the number of individual liver metastatic lesions per animal in comparison to IgG control in a preclinical study. Our novel data suggest that Prrx1b promotes EMT via the Prrx1b-Hgf axis in PDAC. This is the first demonstration of transcriptional factor regulation of the metastatic cascade through EMT plasticity.

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The roles of apoptosis and necroptosis during the onset of chronic pancreatitis (CP) are not fully understood. Here we have developed Spink3^SPINK1/- transgenic mice (termed "SPINK1-in") in which one ablated Spink3 allele is replaced by knocked-in SPINK1. SPINK1-in mice represent a novel, clinically relevant, genetic model of human CP, revealing the mechanisms whereby SPINK insufficiency causes CP. To investigate the roles of apoptosis and necroptosis in chronic pancreatitis, we crossed SPINK1-in mice to CHOP-deficient (Chop^-/-) or Ripk3-deficient (Ripk3^-/-) mice. The progression of pancreatic fibrosis in Chop^-/-; Spink3^SPINK1/- mice compared with that of SPINK1-in mice. We also found pancreas damage was prevented by Ripk3 deletion, suggesting that Ripk3-dependent necroptosis is critical factor for onset of CP.

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Since the identification of mutations in the PRSS1 gene as a cause of hereditary pancreatitis, several pancreatitis susceptibility genes have been identified including the SPINK1 and CPA1 genes. Most of the pancreatitis-associated genes are related to the activation and deactivation of trypsin. Recent studies have suggested that misfolding-induced endoplasmic reticulum stress might be a novel mechanism responsible for genetic variants and pancreatitis. Because about 30% of families with hereditary pancreatitis do not carry mutations in any of the known pancreatitis susceptibility genes, other yet unidentified genes might be involved. A new approach that uses next generation sequencing (NGS) is becoming standardized. Targeted capture of selected regions of interest followed by NGS provides an efficient and cost-effective option. Targeted NGS allowed us to perform rapid screening of the known susceptibility genes simultaneously and gave an overview of potentially pathogenic variants in patients with pancreatitis.

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This review examines the current knowledge about the clinicopathological features, molecular genetics and genetically engineered mouse models (GEMMs) of intraductal papillary mucinous neoplasms of the pancreas (IPMN). IPMN is a cystic neoplasm with dilated ducts filled with mucin. Its appearance is vastly different from the conventional pancreatic ductal carcinoma (PDAC) that forms a solid invasive mass, however, it is also known to be a precursor of PDAC. IPMN harbors somatic mutations in GNAS that encodes G-protein stimulating α subunit (Gsα) as well as KRAS that encodes Kirsten rat sarcoma virus oncogene homologue product (K-RAS), a GTP-binding protein. We have generated a GEMM in which conditionally expresses the mutated GNAS and Kras in the pancreas driven by Ptf1a-Cre. The model mouse develops a multi-cystic tumor composed of dilated ducts lined with papillary neoplastic epithelia, which closely mimics a human IPMN. This model may serve as a unique platform to investigate molecular mechanisms of development and progression as well as better clinical management of IPMN.

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Epigenome regulates gene transcription in response to various extra- cellular stimuli in cells. The system is fine tuned by complex mechanisms including DNA methylation, histone modification, and chromatin structural change. Recent research identified genomic alterations in such epigenome regulatory factors and visualized the landscape of specific epigenomic status in several cancer cells, suggesting the role for epigenome in the initiation and progression of tumors including pancreatic malignancies. Though the critical roles of genetic mutations in pancreatic ductal adenocarcinoma have been well examined, these genetic alterations have not fully explained the complexity of tumor development, still suggesting the involvement of other factors including epigenome regulators. KDM6B is a histone modifying enzyme and has been proposed to be a tumor suppressor, since it activates p16/CDKN2A gene under oncogenic KRAS mutations, thereby inducing senescence in premalignant lesions. Here we showed a novel role for KDM6B-C/EBPα axis in the tumorigenesis of PDAC cells. Our findings emphasize that understandings of cancer epigenome develop a new possibility in targeting strategies against pancreatic tumors.

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Pancreatic cancer leads to increased proliferation, invasion, resistance to anticancer agents and radiation, and metastasis. The epithelial-to-mesenchymal transition (EMT) is a characteristic known to be involved during the progression of cancer cells. We found that gemcitabine (GEM) triggers EMT-like changes of pancreatic cancer. To investigate the molecular mechanism of GEM-induced EMT in cancer cells, we analyzed proteome profiles of cell culture medium to identify proteins that may potentially induce EMT in PANC-1 cells in response to GEM. Following the treatment with GEM, various proteins in the medium were decreased, whereas, heat shock protein 90 (HSP90) was mostly increased. Recombinant HSP90 protein induced morphological changes and EMT-related markers in cancer cells. These results indicate that excretory HSP90 is responsible for GEM-induced EMT in cancer cells and suggest the necessity to establish a therapeutic strategy for preventing such unwanted biological effects induced by chemotherapeutics in pancreatic cancer cells.

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We herein report a case of rapidly advanced spindle cell type anaplastic carcinoma of the pancreas which developed acute pancreatitis. A 51-year old man was admitted with chief complaints of back pain. Laboratory data on initial visit showed high levels of serum amylase and trypsin. Enhanced CT scan showed a low density mass which was 15mm in diameter in the pancreatic head and enlargement of the pancreatic body and tail. An abnormal accumulation of ¹⁸FDG in the pancreatic head was identified by PET-CT. Laboratory data on admission showed high levels of tumor markers (CA19-9, DUPAN-2, Span-1). We diagnosed as pancreatic head cancer which developed acute pancreatitis. Thus, pylorus preserving pancreaticoduodenectomy was performed, and histopathological examination revealed spindle cell type anaplastic carcinoma of the pancreas. Although we performed postoperative chemotherapy, local recurrence and liver metastases occurred one month and three months after surgery, respectively.

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We report a rare surgical case of metachronous multicentric pancreatic cancer with multiple intraductal papillary mucinous neoplasms (IPMN). A 58-year-old woman with diabetes mellitus and a family history of pancreatic cancer (her father suffered from pancreatic cancer), was admitted to our hospital because of backache in November 2008. Distal pancreatectomy was performed for pancreatic cancer of the body concomitant with multiple IPMNs of uncinate process and distal pancreas in April 2009. Histopathological investigation revealed well-differentiated tubular adenocarcinoma concomitant with branch duct type IPMN. The final diagnosis based on general rules of JPS was T3N0M0, Stage III (R0). Although the margin of the surgical specimen was negative for carcinoma, a surgical specimen near the pancreatic stump showed PanIN1A-1B. Thirty-seven months after resection, the serum CA 19-9 value was elevated. Imaging examinations revealed a mass in the remnant pancreas. Forty-six months after the initial surgery, total pancreatectomy with portal vein resection was performed. Although the tumor was pathologically diagnosed as well-differentiated tubular adenocarcinoma, multicentric carcinogenesis was suggested because of histological differentiation from the initial tumor. The main tumor had no continuity with a branch duct type IPMN of the uncinate process. Therefore, the patient was diagnosed as metachronous multicentric pancreatic cancer concomitant with multiple IPMNs.

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A 42-year-old man was referred to our hospital because of mass lesion located in the pancreatic body. Contrast-enhanced CT scan showed a pancreatic body tumor 14mm in diameter, which was hypo dense in early phase and unclear in delayed phase. No capsules or cysts were identified. FDG-PET imaging showed increased uptake in the pancreatic body. We performed EUS-FNA for diagnosis. During the first attempt, we only recognized a few acinar cells leading to the second attempt. The second EUS-FNA material contained a few homogenous cell clusters different from normal pancreatic tissue, however, the clusters did not demonstrate typical pseudopapillary and/or pseudorosette structures frequently observed in SPNs. We suspected SPN because we identified eccentric nuclei and slightly eosinophilic cytoplasm often containing a small perinuclear vacuole. Immunostaining revealed that these cells were positive for β-catenin (abnormal nuclear expression) and CD10. So we preoperatively diagnosed it as SPN. We performed distal pancreatectomy and finally diagnosed it as SPN at the histopathological examination of the resected specimen. Even if an initial analysis did not show typical pseudopapillary structure, we should suspect SPN and perform further examination, including immunostaining, in cases where cells of unknown origin having remarkable intracytoplasmic vacuoles are detected.

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