Primordial germ cells as a potential shared cell of origin for mucinous cystic neoplasms of the pancreas and mucinous ovarian tumors.

Mucinous ovarian tumors (MOTs) morphologically and epidemiologically resemble mucinous cystic neoplasms (MCNs) of the pancreas, sharing a similar stroma and both occurring disproportionately among young females. Additionally, MOTs and MCNs share similar clinical characteristics and immunohistochemical phenotypes. Exome sequencing has revealed frequent recurrent mutations in KRAS and RNF43 in both MOTs and MCNs. The cell of origin for these tumors remains unclear, but MOTs sometimes arise in the context of mature cystic teratomas and other primordial germ cell (PGC) tumors. We undertook the present study to investigate whether non-teratoma-associated MOTs and MCNs share a common cell of origin. Comparisons of the gene expression profiles of MOTs [including both the mucinous borderline ovarian tumors (MBOTs) and invasive mucinous ovarian carcinomas (MOCs)], high-grade serous ovarian carcinomas, ovarian surface epithelium, Fallopian tube epithelium, normal pancreatic tissue, pancreatic duct adenocarcinomas, MCNs, and single-cell RNA-sequencing of PGCs revealed that both MOTs and MCNs are more closely related to PGCs than to either eutopic epithelial tumors or normal epithelia. We hypothesize that MCNs may arise from PGCs that stopped in the dorsal pancreas during their descent to the gonads during early human embryogenesis, while MOTs arise from PGCs in the ovary. Together, these data suggest a common pathway for the development of MCNs and MOTs, and suggest that these tumors may be more properly classified as germ cell tumor variants. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Expression of master regulatory genes of embryonic development in pancreatic tumors.

The expression level of some important master regulators of embryonic development of the pancreas in the tumor samples of this human organ was determined. We found that the transcription of SOX9, GATA4, PDX1, PTF1a, and HNF1b genes in the tumor samples was reduced as compared to the samples of normal pancreatic tissues, and the KLF5 gene expression in the tumor cells was elevated. We assume that all the studied genes, except KLF5, form a single regulatory module that supports the identity of tumor progenitor cells. A simultaneous suppression of expression of these master factors may be critical for the neoplastic transformation of pancreatic cells.

Translating discovery in zebrafish pancreatic development to human pancreatic cancer: biomarkers, targets, pathogenesis, and therapeutics.

Abstract Experimental studies in the zebrafish have greatly facilitated understanding of genetic regulation of the early developmental events in the pancreas. Various approaches using forward and reverse genetics, chemical genetics, and transgenesis in zebrafish have demonstrated generally conserved regulatory roles of mammalian genes and discovered novel genetic pathways in exocrine pancreatic development. Accumulating evidence has supported the use of zebrafish as a model of human malignant diseases, including pancreatic cancer. Studies have shown that the genetic regulators of exocrine pancreatic development in zebrafish can be translated into potential clinical biomarkers and therapeutic targets in human pancreatic adenocarcinoma. Transgenic zebrafish expressing oncogenic K-ras and zebrafish tumor xenograft model have emerged as valuable tools for dissecting the pathogenetic mechanisms of pancreatic cancer and for drug discovery and toxicology. Future analysis of the pancreas in zebrafish will continue to advance understanding of the genetic regulation and biological mechanisms during organogenesis. Results of those studies are expected to provide new insights into how aberrant developmental pathways contribute to formation and growth of pancreatic neoplasia, and hopefully generate valid biomarkers and targets as well as effective and safe therapeutics in pancreatic cancer.

[Prediction of prognosis of pancreatic cancer based on the homing area]. / Voraussage der Prognose des Pankreaskarzinoms in seinem Homing-Areal.

The homing area is a genetically defined location where primary malignancy originates and local recurrences occur. In order to be completely successful, curative resections of malignant tumors have to eradicate the homing area. This is possible in colon resection where the borders of the homing area are distant from the tumor and the lymph nodes can easily be resected to remove possible node metastases. In contrast, the homing area of the pancreas comprises only the gland itself, similar to all other glandular organs. The high specificity of the homing area is demonstrated by the finding that even pancreatic islets are spared by the malignant disease. During fetal development the pancreas loses most of the original dorsal and ventral mesentery. Via short lymphatic pathways, metastatic cells leave the gland in a centrifugal manner and find their way to regional lymph nodes that often share drainage with other neighboring organs. The lymph nodes are arranged in multiple layers and not in flat mesentery-like structures. Radical resections are therefore difficult to achieve.

Clinicopathologic assessment of pancreatic ductal carcinoma located at the head of the pancreas, in relation to embryonic development.

OBJECTIVES: Pancreaticoduodenectomy is performed for pancreatic head cancer that originated from the dorsal or ventral primordium. Although the extent of lymph node (LN) dissection is the same irrespective of the origin, the lymphatic continuities may differ between the 2 primordia. METHODS: Between March 2003 and September 2010, 152 patients underwent pancreaticoduodenectomy for pancreatic cancer. One hundred six patients were assigned into 2 groups according to tumor location on preoperative computed tomography, and their clinical and pathological features were retrospectively analyzed in view of the embryonic development of the pancreas. RESULTS: Sixty of 106 patients were classified with tumors that were derived from the dorsal pancreas (D group) and 46 from the ventral pancreas (V group). The frequency of LN involvement around the middle colic artery (LN 15) in the D group was higher than in the V group (P = 0.008). The rate of additional resection of the pancreas tended to be higher in the D group (P = 0.067). CONCLUSIONS: The present study showed the detailed pattern of spread of pancreatic ductal carcinoma to the LNs and provided important information for determining the optimal surgical strategy.

Genetic susceptibility to pancreatic cancer.

Pancreatic cancer is the fourth leading cause of cancer death in both men and women in the United States. However, it has the poorest prognosis of any major tumor type, with a 5-yr survival rate of approximately 5%. Cigarette smoking, increased body mass index, heavy alcohol consumption, and a diagnosis of diabetes mellitus have all been demonstrated to increase risk of pancreatic cancer. A family history of pancreatic cancer has also been associated with increased risk suggesting inherited genetic factors also play an important role, with approximately 5-10% of pancreatic cancer patients reporting family history of pancreatic cancer. While the genetic basis for the majority of the familial clustering of pancreatic cancer remains unclear, several important pancreatic cancer genes have been identified. These consist of high penetrance genes including BRCA2 or PALB2, to more common genetic variation associated with a modest increase risk of pancreatic cancer such as genetic variation at the ABO blood group locus. Recent advances in genotyping and genetic sequencing have accelerated the rate at which novel pancreatic cancer susceptibility genes have been identified with several genes identified within the past few years. This review addresses our current understanding of the familial aggregation of pancreatic cancer, established pancreatic cancer susceptablity genes and how this knowledge informs risk assessment and screening for high-risk families.

Gastroenteropancreatic neuroendocrine tumor cancer stem cells: do they exist?

Neuroendocrine tumors (NETs) comprise a broad range of neoplasms that share biological and embryological origin. A deeper knowledge in the underlying molecular biology that results in the development and spread of NETs has allowed the use of novel-targeted therapies against angiogenesis and intracellular pathways, key checkpoints that govern growth, and proliferation of these tumors. Unfortunately, the possibility of cure is still far for patients with advanced stages. Cancer stem cells (CSCs) are present in most solid tumors. Nevertheless, there is limited evidence for the presence of CSCs in NETs. In this review, we will discuss the embryonic origin and possible existence of a gastroenteropancreatic neuroendocrine cancer stem cell. Here, we summarize the body of evidence supporting the presence of active embryological pathways like Notch, Wnt-ß-catenin, Hedgehog, or transforming growth factor-ß in NETs. New therapeutic approaches in the field of CSCs seem to have a clear role in the treatment of medulloblastomas and basal cell carcinomas, but their future value in other solid tumor types including NETs remains unclear.

Zebrafish as a model for the study of human cancer.

Zebrafish provide an exciting animal model system for the study of human cancers. During the last few years many zebrafish models of cancer have been generated that recapitulate human hematologic malignancies and solid tumors. Concurrent technological advances have significantly improved the genetic tractability and unique advantage of in vivo imaging in zebrafish, providing a means to dissect the molecular pathways underlying tumor initiation, progression and metastasis. Comparisons of cancer-associated gene expression profiles have demonstrated a high degree of similarity in the gene signatures of specific types of tumor cells in fish and humans, indicating that the contributing genetic pathways leading to cancer are evolutionarily conserved. Furthermore, the high fecundity, optical clarity and small embryo size of zebrafish continue to make it particularly amenable to performing whole-organism small molecule screens to identify targets for therapeutic development. This chapter reviews a wide array of these zebrafish cancer models and illustrates the advantages of the zebrafish system for exploring the molecular mechanisms governing cancer-related cellular processes.

Cyclin-dependent kinase inhibitor Dinaciclib (SCH727965) inhibits pancreatic cancer growth and progression in murine xenograft models.

Pancreatic cancer is one of the most lethal of human malignancies, and potent therapeutic options are lacking. Inhibition of cell cycle progression through pharmacological blockade of cyclin-dependent kinases (CDK) has been suggested as a potential treatment option for human cancers with deregulated cell cycle control. Dinaciclib (SCH727965) is a novel small molecule multi-CDK inhibitor with low nanomolar potency against CDK1, CDK2, CDK5 and CDK9 that has shown favorable toxicity and efficacy in preliminary mouse experiments, and has been well tolerated in Phase I clinical trials. In the current study, the therapeutic efficacy of SCH727965 on human pancreatic cancer cells was tested using in vitro and in vivo model systems. Treatment with SCH727965 significantly reduced in vitro cell growth, motility and colony formation in soft agar of MIAPaCa-2 and Pa20C cells. These phenotypic changes were accompanied by marked reduction of phosphorylation of Retinoblastoma (Rb) and reduced activation of RalA. Single agent therapy with SCH727965 (40 mg/kg i.p. twice weekly) for 4 weeks significantly reduced subcutaneous tumor growth in 10/10 (100%) of tested low-passage human pancreatic cancer xenografts. Treatment of low passage pancreatic cancer xenografts with a combination of SCH727965 and gemcitabine was significantly more effective than either agent alone. Gene Set Enrichment Analysis identified overrepresentation of the Notch and Transforming Growth Factor-ß (TGF-ß) signaling pathways in the xenografts least responsive to SCH727965 treatment. Treatment with the cyclin-dependent kinase inhibitor SCH727965 alone or in combination is a highly promising novel experimental therapeutic strategy against pancreatic cancer.

Gene expression profiling provides insights into the pathways involved in solid pseudopapillary neoplasm of the pancreas.

Solid-pseudopapillary neoplasms (SPNs) are rare human pancreatic neoplasms usually associated with a good prognosis. In contrast to other pancreatic tumours, aberrant activation of the Wnt-beta-catenin pathway appears to be a constant feature in SPN. Aside from activation of the Wnt-beta-catenin pathway, little is known about biological pathways deregulated in SPN. We carried out transcriptome profiling of SPN to gain insights into the pathogenesis of these tumours. As expected, the over-expression of AXIN2, TBX3, SP5 and NOTUM demonstrated activation of the beta-catenin pathway. Members of the Notch pathway (HEY1, HEY2, NOTCH2) were also up-regulated, relative to their expression in ductal adenocarcinomas (DAC) or pancreatic endocrine tumours (PET). Other genes, such as EDN3, HAND2, netrin-G2 and the receptor netrin-G1 ligand, involved in neural crest differentiation, were also identified as altered. Increased levels of SOX10 and TuJ-1 proteins were also indicative of neural-like differentiation. In conclusion, SPN display a complex expression profile, distinct from that observed in PET and DAC and involving both the beta-catenin and Notch pathways, together with expression of neural differentiation markers.

Opposing effects of n-6 and n-3 polyunsaturated fatty acids on pancreatic cancer growth.

OBJECTIVES: Epidemiologic studies suggest that fish oil, rich in n-3 polyunsaturated fatty acids (PUFA), possesses antitumor activity, whereas n-6 PUFAs may stimulate the development of cancers. The aim of this study was to evaluate the effects of n-6 and n-3 PUFAs on the growth of pancreatic cancer. METHODS: The n-6 PUFA arachidonic acid (AA) stimulated the growth of cyclooxygenase (COX) 2 positive human pancreatic cancer (PaCa) cells, which was mediated by COX-2 generated prostaglandin E2 (PGE2) binding to EP2 and EP4 receptors. In contrast, the n-3 PUFA eicosapentaenoic acid decreased the growth of COX-2-positive and COX-2-negative PaCa cells. The COX-2-dependent mechanism of eicosapentaenoic acid was mediated by binding of PGE3 to EP2 and EP4 receptors. Dietary intake of n-3 PUFAs decreased the growth of pancreatic cancers in a xenograft model, which was accompanied by a decrease of PGE2 and an increase of PGE3 in the tumors. CONCLUSIONS: Our studies provide evidence that n-3 PUFAs possess antitumor activities, whereas n-6 PUFAs stimulate pancreatic tumor growth. The opposite effects of n-3 and n-6 PUFAs are mediated by the formation of different prostaglandin species. n-3 PUFAs may prove beneficial as monotherapy or combination therapy with standard chemotherapeutic agents in pancreatic cancer patients.

Nestin expression in neoplastic, fetal, and adult pancreatic endocrine cells.

BACKGROUND/AIMS: Pancreatic endocrine cells are multifunctional, differentiated cells originating from the differentiation of foregut endodermal precursors. Identification and transplantation of endocrine precursor cells appear to be the ultimate solution to diabetes mellitus, which requires lifelong treatment. Knowledge about specific markers that are used in the determination of precursor cells is limited. METHODOLOGY: In this study, the expression of nestin in well-differentiated pancreatic neuroendocrine tumors (n = 17) was investigated. In addition, developmental characteristics of nestin expression in the fetal (n = 5) and adult pancreas (n = 5) were examined. RESULTS: Findings indicated that nestin is expressed in proliferating and metabolically active cells, such as endothelium, independent of developmental and neoplastic processes, rather than endocrine precursor cells of the pancreas. CONCLUSIONS: In this study, it was concluded that nestin cannot be used as the only marker to identify pancreatic endocrine cell precursors for transplantation.

[Cystadenomas with ovarian stroma in liver and pancreas: indications of embryonic migration of the gonadal epithelium]. / Cystadenomen met ovarieel stroma in lever en pancreas: aanwijzingen voor embryonale migratie van gonadaal epitheel.

OBJECTIVE: To provide an embryological explanation for the presence of ovarian stroma in cystadenomas of the liver and pancreas. DESIGN: Investigation of patients and embryos. METHOD: From 1997 to 2001 in the Academic Medical Centre, Amsterdam, the Netherlands, nine women were treated for a cystadenoma with ovarian stroma, six of which were situated in the liver and three in the tail of pancreas. In one patient with a cystadenoma in the liver, malignant changes had taken place. In embryos at 5-8 weeks development, the regional differences in the morphology of the epithelium of the peritoneal cavity and the position of the gonads in relation to the embryonic liver, pancreas and spleen were examined. RESULTS: In the foetal period before the gonads begin to descend, they are situated directly dorsal to the liver, tail of pancreas and spleen, but are separated from these by the peritoneal cavity. The cells that cover the urogenital folds distinguish themselves from those elsewhere in the peritoneal cavity as they are bulging in shape as opposed to flattened. This activated morphology suggests that on physical contact with a neighbouring organ the cells covering the gonads may become detached and lodge in that organ. CONCLUSION: It is likely that cystadenomas of the liver and pancreas have their origin in the cells that cover the embryonic gonads. The anomalous morphology of these covering cells in fact suggests that they are relatively easily mobilized. They are probably comparable with inoculation metastasis in the coelomic cavity. Taking the chance of malignant transformation of a cystadenoma into account, the treatment of choice is radical resection of the abnormality.

Developmental aspects of early pancreatic cancer.

The specific cell of origin responsible for generating pancreatic intraepithelial neoplasia and pancreatic ductal adenocarcinoma remains unknown. During development, epithelial stem cells within embryonic pancreatic epithelium give riseto mature acinar, ductal, and islet elements. Emerging evidence suggests that cells with precursor potential also exist within adult pancreas, resulting in significant developmental plasticity among both endocrine and exocrine cell types. In this review, the contribution of developmental plasticity in initiating pancreatic metaplasia and neoplasia is considered, and evidence supporting a role for epithelial stem cells in pancreatic cancer is discussed.

Pancreatoblastoma and solid and cystic papillary tumor: two tumors related to pancreatic ontogeny.

Two tumors of the pancreas are related to pancreatic ontogeny. The pancreatoblastoma is a tumor of children, more commonly boys than girls and progresses with a slow, sluggishly malignant course. Surgery successfully controls the disease in about half the cases. Morphologic and immunohistochemical studies reveal undifferentiated areas, ductular areas, acinar areas, and occasionally neuroendocrine differentiation. Very characteristic is the presence of nodules of squamous epithelium. These features reflect the potencies of the pancreatic anlage somewhat earlier than the fourteenth week of development. The solid and cystic papillary epithelial tumor of the pancreas is a tumor of adolescent and young adult females, often non-Caucasian. Surgical excision is often successful, but deaths from local persistence and metastases have been described. These tumors have features of ductulo-acinar neoplasms of uncommitted pancreatic primordia exceptionally with neuroendocrine differentiation.

Defective lens fiber differentiation and pancreatic tumorigenesis caused by ectopic expression of the cellular retinoic acid-binding protein I.

All-trans retinoic acid, a metabolite of retinol, is a possible morphogen in vertebrate development. Two classes of cellular proteins, which specifically bind all-trans retinoic acid, are thought to mediate its action: the nuclear retinoic acid receptors (RAR alpha, beta, gamma), and the cytoplasmic binding proteins known as cellular retinoic acid-binding proteins I and II (CRABP I and II). The function of the retinoic acid receptors is to regulate gene transcription by binding to DNA in conjunction with the nuclear retinoid X receptors (RXR alpha, beta, gamma), which in turn have 9-cis retinoic acid as a ligand. Several lines of evidence suggest that the role of the cellular retinoic acid-binding proteins is to control the concentration of free retinoic acid reaching the nucleus in a given cell. Here, we have addressed the role of the cellular retinoic acid-binding protein I in development by ectopically expressing it in the mouse lens, under the control of the alpha A-crystallin promoter. We show that this ectopic expression interferes with the development of the lens and with the differentiation of the secondary lens fiber cells, causing cataract formation. These results suggest that correct regulation of intracellular retinoic acid concentration is required for normal eye development. In addition, the generated transgenic mice also present expression of the transgene in the pancreas and develop pancreatic carcinomas, suggesting that overexpression of the cellular retinoic acid-binding protein is the cause of the tumors. These results taken together provide evidence for a role of the cellular retinoic acid-binding protein in development and cell differentiation. The relevance of these findings to the possible role of the cellular retinoic acid-binding proteins in the transduction of the retinoic acid signal is discussed.

[The modes of spread of pancreas head cancer based on difference of the pancreatic anlagen].

Embryologically the pancreas head consists of a dorsal and a ventral portion and these were able to be differentiated by the shape of the islets and the density of pancreatic polypeptide (pp) cells. We examined histologically the modes of spread of carcinoma of the head of the pancreas. The material were 15 cases with T1 and T2 cancer resected (T1;8;T2;7) and included 8 tumors arising from a ventral pancreas and 7 dorsal. We conclude that most of pancreas head cancers arising from a ventral pancreas involved the retropancreatic soft tissue at the early stage, and those arising from a dorsal pancreas showed an apparent tendency of a spread to the epithelial linings of the main pancreatic duct.