The link between exocrine pancreatic cancer and the endocrine pancreas

An Unusual Case of Dual Pancreatic Tumors

We report a simultaneous occurrence of pancreatic adenocarcinoma and pancreatic neuroendocrine tumor. A 64-year-old woman presented with abdominal pain and weight loss. Abdominal computed tomography revealed a pancreatic head mass with a mesenteric artery encasement. Endoscopic ultrasound revealed a second mass in the tail of the pancreas. Pathology reported adenocarcinoma of the head of the pancreas and a neuroendocrine tumor in the tail of the pancreas. The neuroendocrine tumor was nonfunctional, with no symptoms or signs present on assessment. The patient had advanced unresectable carcinoma, so she was treated with chemotherapy.

Rate of clinically significant postoperative pancreatic fistula in pancreatic neuroendocrine tumors

BACKGROUND

In 2005, the International Study Group of Pancreatic Fistula (ISGPF) developed a definition and grading system for postoperative pancreatic fistula (POPF). The authors sought to determine the rate of POPF after enucleation and/or resection of pancreatic neuroendocrine tumors (PNET) and to identify clinical, surgical, or pathologic factors associated with POPF.

METHODS

A retrospective analysis of pancreatic enucleations and resections performed from March 1998 to April 2010. We defined a clinically significant POPF as a grade B that required nonoperative intervention and grade C.

RESULTS

One hundred twenty-two patients were identified; 62 patients had enucleations and 60 patients had resections of PNET. The rate of clinically significant POPF was 23.7 % (29/122). For pancreatic enucleation, the POPF rate was 27.4 % (17/62, 14 grade B, 3 grade C). The pancreatic resection group had a POPF rate of 20 % (12/60, 10 grade B, 2 grade C). This difference was not significant (p = 0.4). In univariate analyses, patients in the enucleation group with hereditary syndromes (p = 0.02) and non-insulinoma tumors (p = 0.02) had a higher POPF rate. Patients in the resection group with body mass index (BMI) > 25 (p < 0.01), multiple endocrine neoplasia type 1 (MEN-1; p < 0.01) and those who underwent simultaneous multiple procedures (p = 0.02) had a higher POPF rate. Multivariate analyses revealed that hereditary syndromes were able to predict POPF in the enucleation group, while having BMI > 25 and increasing lesion size were also associated with POPF in the group undergoing resection.

CONCLUSIONS

We found a clinically significant POPF rate after surgery in PNET to be 23.7 % with no difference by the type of operation. Our POPF rate is comparable to that reported in the literature for pancreatic resection for other types of tumors. Certain inherited genetic diseases-von Hippel-Lindau disease (VHL) and MEN-1-were associated with higher POPF rates.

Synchronous epithelial and neuroendocrine cancers of the pancreas: case series of a rare occurrence

The presence of neuroendocrine cells in adenocarcinomas is not an unusual finding and is well described in gastrointestinal tract cancers, eg, colorectal cancer and gastric cancer. Genetic analysis of such tumors has suggested a common multipotent progenitor stem cell origin. The prognostic significance of neuroendocrine cells in adenocarcinoma cells is unclear. There is a scant literature on synchronous pancreas ductal adenocarcinoma and pancreas neuroendocrine tumors. We report 2 cases with a purpose of discussing management strategies, prognosis, and potential etiologies of this rare presentation.

Islet cells contribute to pancreatic carcinogenesis in an animal model

OBJECTIVES

In the hamster model, pancreatic ductal adenocarcinoma develops after treatment with N-nitrosobis-(2-oxopropyl)amino (BOP). In this model, Langerhans islets play a central role in carcinogenesis. In contrast, treatment with BOP in rats and mice did not result in cancer development. We investigated whether pancreatic tumors develop after orthotopic implantation of hamster islets into severe combined immunodeficiency mouse pancreases and subsequent treatment with BOP. This occurrence would suggest that pancreatrophic carcinogens are metabolized by islet cells.

METHODS

Twenty-four severe combined immunodeficiency mice were separated into 2 groups of 12 animals. Five hundred hamster islets were implanted in the splenic lobe of the mouse pancreases in the treatment group, whereas animals of the control group received a sham operation. All animals were treated with BOP for 5 weeks. One year later, the animals were killed and investigated for tumors.

RESULTS

Carcinomas developed in 3 animals in the treatment group and none in the control group. The tumors displayed the histomorphological phenotype pancreatic ductal adenocarcinoma.

CONCLUSIONS

Islet cells seem to play a role in pancreatic carcinogenesis in this animal model and therefore represent useful targets for future investigations on the putative role of islet cells during pancreatic ductal adenocarcinoma tumorigenesis.

Pancreatic endocrine tumors

Pancreatic endocrine tumors have been steadily growing in incidence and prevalence during the last two decades, showing an incidence of 4-5/1,000,000 population. They represent a heterogeneous group with very varying tumor biology and prognosis. About half of the patients present clinical symptoms and syndromes related to substances released from the tumors (Zollinger-Ellison syndrome, insulinoma, glucagonoma, etc) and the other half are so-called nonfunctioning tumors mainly presenting with symptoms such as obstruction, jaundice, bleeding, and abdominal mass. Ten percent to 15% of the pancreatic endocrine tumors are part of an inherited syndrome such as multiple endocrine neoplasia type 1 (MEN-1), von Hippel-Lindau (VHL), neurofibromatosis, or tuberousclerosis. The diagnosis is based on histopathology demonstrating neuroendocrine features such as positive staining for chromogranin A and specific hormones such as gastrin, proinsulin, and glucagon. Moreover, the biochemical diagnosis includes measurement of chromogranins A and B or specific hormones such as gastrin, insulin, glucagon, and vasoactive intestinal polypeptide (VIP) in the circulation. In addition to standard localization procedures, radiology (computed tomography [CT] scan, magnetic resonance imaging [MRI], ultrasound [US]), somatostatin receptor scintigraphy, and most recently positron emission tomography with specific isotopes such as (11)C-5 hydroxytryptamin ((11)C-5-HTP), fluorodopa and (68)Ga-1,4,7,10-tetra-azacyclododecane-N,N',N″,N‴-tetra-acetic acid (DOTA)-octreotate are performed. Surgery is still one of the cornerstones in the management of pancreatic endocrine tumors, but curative surgery is rarely obtained in most cases because of metastatic disease. Debulking and other cytoreductive procedures might facilitate systemic treatment. Cytotoxic drugs, biological agents, such as somatostatin analogs, alpha interferons, mammalian target of rapamycin (mTOR) inhibitors and tyrosine kinase inhibitors are routinely used. Tumor-targeted radioactive treatment is available in many centres in Europe and is effective in patients with tumors that express high content of somatostatin receptors type 2 and 5. In the future, treatment will be based on tumor biology and molecular genetics with the aim of so-called personalized medicine.

Solitary concomitant endocrine tumor and ductal adenocarcinoma of pancreas

Pancreatic tumors with combined exocrine and endocrine features are rare. Most reported cases are classified as mixed exocrine and endocrine carcinoma of the pancreas. We report the first case of solitary concomitant endocrine tumor and ductal adenocarcinoma of the pancreas. A 58-year-old patient was admitted for uncontrolled diabetes mellitus and body weight loss. The tumor was fortuitously discovered in the pancreatic tail after a tumor survey panel. Grossly, the solitary tumor had a central fibrous band that clearly divided it into two parts. On microscopic examination, the tumor contained both endocrine and exocrine components distinctly separated by the central fibrous band. The exocrine part showed a poorly-differentiated adenocarcinoma. The endocrine part was strongly immunoreactive to chromogranin, synaptophysin and glucagon. We reviewed the literature on pancreatic tumors with combined exocrine and endocrine features. A simple classification for this group of neoplasms is suggested, including five types: amphicrine, mixed, collision, solitary concomitant and multiple concomitant.

Spontaneous induction of murine pancreatic intraepithelial neoplasia (mPanIN) by acinar cell targeting of oncogenic Kras in adult mice

Pancreatic ductal adenocarcinoma (PDAC) is believed to arise through a multistep model comprised of putative precursor lesions known as pancreatic intraepithelial neoplasia (PanIN). Recent genetically engineered mouse models of PDAC demonstrate a comparable morphologic spectrum of murine PanIN (mPanIN) lesions. The histogenesis of PanIN and PDAC in both mice and men remains controversial. The most faithful genetic models activate an oncogenic Kras(G12D) knockin allele within the pdx1- or ptf1a/p48-expression domain of the entire pancreatic anlage during development, thus obscuring the putative cell(s)-of-origin from which subsequent mPanIN lesions arise. In our study, activation of this knockin Kras(G12D) allele in the Elastase- and Mist1-expressing mature acinar compartment of adult mice resulted in the spontaneous induction of mPanIN lesions of all histological grades, although invasive carcinomas per se were not seen. We observed no requirement for concomitant chronic exocrine injury in the induction of mPanIN lesions from the mature acinar cell compartment. The acinar cell derivation of the mPanINs was established through lineage tracing in reporter mice, and by microdissection of lesional tissue demonstrating Cre-mediated recombination events. In contrast to the uniformly penetrant mPanIN phenotype observed following developmental activation of Kras(G12D) in the Pdx1-expressing progenitor cells, the Pdx1-expressing population in the mature pancreas (predominantly islet beta cells) appears to be relatively resistant to the effects of oncogenic Kras. We conclude that in the appropriate genetic context, the differentiated acinar cell compartment in adult mice retains its susceptibility for spontaneous transformation into mPanIN lesions, a finding with potential relevance vis-à-vis the origins of PDAC.

Somatostatin receptor-1 induces cell cycle arrest and inhibits tumor growth in pancreatic cancer

Functional somatostatin receptors (SSTR) are lost in human pancreatic cancer. Transfection of SSTR-1 inhibited pancreatic cancer cell proliferation in vitro. We hypothesize that stable transfection of SSTR-1 may inhibit pancreatic cancer growth in vivo possibly through cell cycle arrest. In this study, we examined the expression of SSTR-1 mRNA in human pancreatic cancer tissue specimens, and investigated the effect of SSTR-1 overexpression on cell proliferation, cell cycle, and tumor growth in a subcutaneous nude mouse model. We found that SSTR-1 mRNA was downregulated in the majority of pancreatic cancer tissue specimens. Transfection of SSTR-1 caused cell cycle arrest at the G(0)/G(1) growth phase, with a corresponding decline of cells in the S (mitotic) phase. The overexpression of SSTR-1 significantly inhibited subcutaneous tumor size by 71% and 43% (n = 5, P < 0.05, Student's t-test), and inhibited tumor weight by 69% and 47% (n = 5, P < 0.05, Student's t-test), in Panc-SSTR-1 and MIA-SSTR-1 groups, respectively, indicating the potent inhibitory effect of SSTR-1 on pancreatic cancer growth. Our data demonstrate that overexpression of SSTR-1 significantly inhibits pancreatic cancer growth possibly through cell cycle arrest. This study suggests that gene therapy with SSTR-1 may be a potential adjuvant treatment for pancreatic cancer.

Reg genes are CCK2 receptor targets in ElasCCK2 mice pancreas

We previously demonstrated that expression of the gastrin receptor, CCK2R, in pancreatic acini of transgenic ElasCCK2 mice induced alteration of acinar morphology and differentiation, increased sensitivity to a carcinogen and development of preneoplastic lesions and tumours. Reg proteins are suggested to be involved in pancreatic cancer and in regeneration of endocrine pancreas. Reg I gene is a known target of gastrin. We examined whether an expression of CCK2R in the pancreatic acini of ElasCCK2 mice is linked to induction of Reg proteins expression. We analyzed Reg expression by Western-blot and immunohistochemistry in pancreas from ElasCCK2 and control mice. Islet neogenesis, glucose homeostasis, insulin secretion and content were also evaluated. Reg I is exclusively produced in acini in ElasCCK2 and control mice. In tumoral pancreas, Reg I and Reg III proteins are expressed in duct-like cells in preneoplastic lesions or in the periphery of tumours and in adjacent acini. The expression of Reg III proteins is increased in ElasCCK2 pancreas before the development of preneoplastic lesions in a subpopulation of islet cells and in small islet-like cell clusters dispersed within the acinar tissue. Several criteria of an enhanced neogenesis are fulfilled in ElasCCK2 pancreas. Moreover, ElasCCK2 mice have an improved response to glucose load, an increased insulin secretion and a doubling of insulin content compared to control mice. We show that Reg proteins are targets of CCK2R activation and are induced during early steps of carcinogenesis in ElasCCK2 mice pancreas. Alterations of exocrine tissue homeostasis in ElasCCK2 pancreas concomitantly activate regenerative responses of the endocrine pancreas possibly linked to paracrine actions of Reg III proteins.

Poorly differentiated endocrine carcinoma and intraductal papillary-mucinous neoplasm of the pancreas: Description of an unusual case

Neuroendocrine tumors and intraductal papillary-mucinous neoplasms constitute histologically distinctive but relatively rare entities among pancreatic tumors. Collision of these tumors is extremely rare and causes several diagnostic problems regarding the histopathologic differential diagnosis of other pancreatic epithelial tumors. The question of whether the neoplastic populations originate from common progenitor cell or whether they represent only a fortuitous association has not been sufficiently explained. Here, we describe a new case of poorly differentiated endocrine carcinoma combined with an intraductal papillary-mucinous neoplasm. To disclose the relationship between the two histologic components, neuroendocrine differentiation was studied by confocal laser scanning microscopy using double immunofluorescence labeling with chromogranin-A and CD57 antibodies. Our results revealed a co-localization of both antigens in neuroendocrine cells of the intraductal papillary-mucinous neoplasm. The finding has previously been described in non-neoplastic neuroendocrine cells. Cells forming poorly differentiated endocrine carcinoma showed a wide heterogeneity in immunoreactions. Our results do not indicate a potential histogenetic similarity between these two neoplasms, which are dissimilar histologically, and underline the previous thesis that cells in intraductal papillary-mucinous neoplasm revealing neuroendocrine differentiation represent only a non-neoplastic cell admixture.

Pancreatic cancer microenvironment

Pancreatic ductal adenocarcinoma remains an extremely aggressive malignancy that is virtually therapy-resistant and has therefore one of the worst prognoses of all human cancers. The focus of research, which had been placed mostly on genetic and epigenetic alterations of the cancer cells themselves, has shifted gradually towards the microenvironment. The cancer microenvironment consists of various components, including fibroblasts, endothelial cells, immune cells, and endocrine cells, that interact with each other and the cancer cells in a complex fashion. This interplay has implications for pancreatic cancer cell growth, migration and invasion, angiogenesis, and immunological recognition of cancer cells. Evidence is accumulating that the cancer microenvironment plays an active role in disease progression, and efforts are being made to target this interplay between cancer cells and host cells to improve the outcome of this deadly disease.

Endocrine tumours of the pancreas

Endocrine pancreatic tumours (EPTs) are uncommon tumours occurring in approximately 1 in 100,000 of the population, representing 1-2% of all pancreatic neoplasms. Some of the tumours may be part of multiple endocrine neoplasia type one (MEN-1) syndrome or von Hippel-Lindau (vHL) disease. EPTs are classified as functioning or non-functioning tumours on the basis of their clinical manifestation. The biochemical diagnosis of EPT is based on hormones and amines released. Besides specific markers such as insulin, there are also general tumour markers such as chromogranin A, which is the most valuable marker and has been reported to be increased in plasma in 50-80% of patients with EPTs and correlates with tumour burden. The location of endocrine tumours of the pancreas includes different techniques, from endoscopic investigations to scintigraphy (e.g. somatostatin receptor scintigraphy) and positron emission tomography. The medical treatment of endocrine pancreatic tumours consists of chemotherapy, somatostatin analogues and alpha-interferon. None of these can cure a patient with malignant disease. In future, therapy will be custom-made and based on current knowledge of tumour biology and molecular genetics.

Are there any stem cells in the pancreas?

A vast number of studies indicate the presence of stem/progenitor cells virtually in all tissues in adult organs, particularly in bone marrow. Recent studies, however, cast doubt about the existence of true stem cells in adult tissue. The complex integrity of several cells with distinct morphologic and functional properties in the mature pancreas confers an appropriate status for stem cell research. Several different types of cells residing in the islets or in the ductal epithelium have been proposed as adult pancreatic stem cells or progenitor cells. However, these reports do not provide conceivable proof for the presence of true pancreatic stem cells. On the other hand, there is considerable evidence indicating transdifferentiation of all adult pancreatic cells into each other, and under proper conditions, to nonpancreatic cells including oncocytes and hepatocytes. Observations pertaining to the putative pancreatic stem cells, transdifferentiation ability of the differentiated mature pancreatic cells in the normal and diseased pancreas will be discussed, and our own findings supporting the transdifferentiation pathway are presented in this article.

Endocrine tumor and intraductal papillary mucinous neoplasm of the pancreas: a fortuitous association?

OBJECTIVES

Pancreatic endocrine tumors (PETs) and intraductal papillary mucinous neoplasms (IPMNs) of the pancreas are rare diseases of the pancreas. Cases of association of endocrine and exocrine neoplasms of the pancreas have been reported, corresponding to mixed or amphicrine tumors. The aim of this report is to describe a series of 6 patients with an original association of IPMN and PET of the pancreas.

METHODS

Among 108 and 103 patients operated on in our center between January 1997 and December 2003 for PETs and IPMNs, respectively, we identified 6 patients with both PET and IPMN, diagnosed on pathologic examination with an immunohistochemical study.

RESULTS

Preoperative diagnosis was unspecified pancreatic tumor (n = 1), IPMN (n = 2), and association of PET and IPMN (n = 3). IPMN involved the main pancreatic duct in 4 patients and was classified as benign (n = 4), borderline (n = 1), or malignant noninvasive (n = 1). PETs measured 1.1 to 3 cm and were malignant in 1 patient (lymph node invasion). When analyzed by immunohistochemistry, 2 cases expressed glucagon, 1 expressed somatostatin, and 1 expressed insulin.

CONCLUSION

This study describes a new aspect of endocrine-exocrine pancreatic neoplasm association. The frequency of the association of PET and IPMN is too large to be fortuitous. Further studies are needed to understand its mechanism.

Molecular targeting of pancreatic disorders

During the last decade significant advances in gene therapy have made it possible to treat various pancreatic disorders in both animal models and in humans. For example, insulin gene delivery to non-beta-cell tissues has been shown to reverse hyperglycemia in diabetic mice, and islet transplantation, based on in vitro differentiation of beta cells and concomitant gene targeting to prevent host autoimmune responses, has become more feasible. Additionally, introduction of the glucokinase regulatory protein and protein kinase C-zeta have been shown to improve glucose tolerance in non-insulin-dependent diabetes mellitus animal models. Pancreatic cancer studies utilize several DNA-based strategies for tumor treatment including introduction of tumor suppressor genes, suppression of oncogenes, suicide gene/prodrug therapy, and restricted replication-competent virus therapy. Tumor-specific targeting is an important part of suicide gene therapy, and tumor-specific promoters are used for cell-specific targeting. Tumor-specific suicide gene therapy directed by the rat insulin promoter has been used to eliminate insulinoma tumors in a mouse model. This review compiles a compendium of information related to the treatment of pancreatic disorders using gene therapy.

Ductal and acinar differentiation in pancreatic endocrine tumors

Rare pancreatic endocrine tumors consisting of both exocrine and endocrine components have been reported sporadically. We investigated the ductal and acinar differentiation in pancreatic endocrine tumors. In immunohistochemical studies of 28 pancreatic endocrine tumors, staining with anti-carcinoembryonic antigen (CEA) or CA19-9 antibody indicated ductal differentiation, while staining with anti-amylase or anti-trypsin antibody indicated acinar differentiation. K-ras gene mutations and p53 gene alterations also were studied. Ten tumors were immunoreactive for CEA or CA19-9. Five tumors diffusely immunoreactive for CEA or CA19-9, in addition to endocrine markers, were diagnosed as duct-endocrine cell tumors of the pancreas. Two tumors diffusely immunoreactive for CEA or CA19-9 and also for pancreaticogut hormones as well as endocrine markers were diagnosed as duct-acinarendocrine cell tumors. These tumors showed uniform histologic features and synchronous ductal, acinar, and endocrine differentiation, distinct from the coexisting different cellular populations seen in collision tumors. All tumors were malignant. These duct-endocrine cell tumors or duct-acinar- endocrine cell tumors of the pancreas may be derived from a stem cell that retains the capability of expressing either an exocrine or endocrine phenotype. Only one K-ras gene mutation and no p53 gene alterations were detected in these tumors, which suggests that they constitute an entity with a different origin than ductal carcinomas.

Mixed ductal-pancreatic polypeptide-cell carcinoma of the pancreas

AIMS

Mixed ductal-endocrine carcinomas of the pancreas are rare tumours with 10 cases reported in the English literature. We report the first case with a polypeptide-cell component.

METHODS AND RESULTS

: The tumour was fortuitously discovered in a 72-year-old woman during the exploration of an endometrial adenocarcinoma. It measured 100 mm and was located in the tail of the pancreas. On microscopic examination two intermingled endocrine and exocrine components were present. The endocrine component consisted of trabeculae and solid nests composed of cells immunoreactive for chromogranin A, synaptophysin and pancreatic polypeptide, but negative for p53 and Bcl-2 proteins. The exocrine component was composed of tubules lined by atypical cylindrical cells immunoreactive for CK19, CEA, p53 and Bcl-2. The stroma of the endocrine component contained amyloid deposits.

CONCLUSION

Mixed ductal-endocrine carcinomas of the pancreas are often described in middle-aged patients. The tumours are usually large and located in the head of the pancreas. An endocrine syndrome is rare and the prognosis is often unfavourable. We report the first case of mixed endocrine-exocrine carcinoma of the pancreas with a pancreatic polypeptide-cell component. The histogenesis of mixed carcinoma of the pancreas is still uncertain but the over-expression of p53 and Bcl-2 could play a major role in the neoplastic progression of the ductal component.

Pancreatic cell lines: a review

Pancreatic cancer has an extremely poor prognosis and lacks early diagnostic and therapeutic possibilities, mainly because of its silent course and explosive fatal outcome. The histogenesis of the disease and early biochemical and genetic alterations surrounding carcinogenesis are still controversial. In vitro studies offer a useful tool to study physiologic, pathophysiologic, differentiation, and transformation processes of cells and to understand some of these shortcomings. The extreme difficulties in isolating individual pancreatic cells and their purification by maintaining their native characteristics have limited research in this area. This review is intended to present and discuss the current availability of rodent and pancreatic cell lines, their differences as well as the difficulties, limitations, and characteristics of these cultured cells. Discussed are in vitro models; ductal, islet, and acinar cell culture; cell differentiation; cell transformation, including genetic and chromosomal alterations; as well as tumor cell markers. Also addressed are the advantages and problems associated with the cell culture in humans and rodents. Advancements in tissue culture technique and molecular biology offer steady progress in this important line of research. The improved methods not only promise the establishment of beta-cell cultures for the treatment of diabetes, but also for studying sequential genetic alterations during pancreatic carcinogenesis and in understanding the tumor cell origin.

Transdifferentiation of human islet cells in a long-term culture

It has been established that ductal cells or precursor cells within the ductal tree of the pancreas can differentiate into islet cells. Although islet cells can also form exocrine cells, it is unclear whether they arise from precursor (stem) cells or from mature endocrine cells by transdifferentiation. Using a defined culture medium and technique for islet purification, for the first time we were able to maintain human islets in culture for more than a year. Multilabeling immunohistochemical and immunoelectron microscopic examination of the islets at different days of culture using islet cell markers (antibodies to hormones, neuron-specific enolase, chromogranin A) and ductal cell markers (cytokeratins 7 and 19, carbonic anhydrase II, DU-PAN2, CA 19-9, and MUC1) revealed that endocrine cells gradually transdifferentiate to ductal, acinar, and intermediary cells. Although islet hormone secretion ceased after day 28 in culture, endocrine cells were still detectable at day 60. However, later, all endocrine and exocrine cells were replaced by undifferentiated cells that expressed neuron-specific enolase, chromogranin A, laminin, vimentin, cytokeratin 7 and 19, alpha-1-antitrypsin, transforming growth factor-alpha, and epidermal growth factor receptor. Our data thus show that, under proper conditions, human islets can be maintained in vitro over a long period and that, in the culture condition, islet cells seem to transdifferentiate to exocrine cells and undifferentiated cells, which may be considered pancreatic precursor (stem) cells.

Molecular pathogenesis of pancreatic ductal adenocarcinoma and clinical implications

Pancreatic ductal adenocarcinoma (PDAC) is a significant cause of cancer death worldwide. PDAC is also one of the best-studied cancers with regard to molecular pathogenesis. The chief risk factors associated with PDAC are smoking and pancreatitis, in addition genetic predisposition seems to play a major role. This genetic predisposition may in some cases be indirect, for example via the elevated risk of pancreatitis seen in patients with hereditary pancreatitis (HP). The elucidation of the molecular causes of PDAC has enabled the provision of secondary screening for PDAC in conditions such as HP. This review is concerned with the molecular pathogenesis of PDAC and the application of this basic scientific understanding into state-of-the-art clinical practice.

Selected features of nonendocrine pancreatic cancer

We survey some interesting features of gene expression in nonendocrine pancreatic cancer, the response to some less widely known agents as they impact on pancreatic cell proliferation and programmed death, and several developing approaches to therapy. The proliferative and cellular suicide responses of Panc-1 cells to the free radical spin trap, NTBN, and to the 5-lipoxygenease inhibitor, MK 886, the latter assessed with CLONTECH Atlas Human cDNA Array 1, are reviewed. Difficulties in identifying those factors whose suppression or augmentation could result in inhibition of malignantly transformed cell properties are considered.

The patterns of extrainsular endocrine cells in pancreatic cancer

Abnormal glucose tolerance and frank diabetes mellitus develop in up to 80% of pancreatic cancer patients. Islets within these tumors show a decreased number of beta cells and increased number of alpha cells. The reduced number of beta cells could induce beta cell neogenesis in extrainsular tissue to compensate for the loss of insulin in islets. On the other hand, because the beta cell depletion in pancreatic cancer seems to be the effect of substances released by cancer cells, suppression of extrainsular endocrine cells is expected. We compared the pattern of extrainsular endocrine cells in pancreatic cancer patients with normal pancreas as well as chronic pancreatitis, which is known to be associated with impaired glucose tolerance or frank diabetes. As in the normal tissue, extrainsular endocrine cells were found in chronic pancreatitis and pancreatic cancer. However, in the chronic pancreatitis specimens insulin cells were the predominant cell type, whereas in pancreatic cancer specimens more glucagon than insulin cells were found, although the differences were statistically insignificant. Thus, our results indicate that the alteration of beta cells in pancreatic cancer patients is mainly restricted to the endocrine cells within the islets and that there is no compensatory proliferation of beta cells.

Molecular prognostic markers in pancreatic cancer

BACKGROUND

Pancreatic cancer is one of the most aggressive human tumors and is virtually incurable. Its incidence in the United States has tripled in the past 50 years. The tumor is a frequent cause of cancer death in both men and women. The current treatment options are inadequate and probably reflect the fact that the etiologic factors and the pathogenesis of pancreatic cancer are unknown.

METHODS

The author reviewed recent studies describing some of the molecular alterations that may play a role in pancreatic carcinogenesis.

RESULTS

Most pancreatic tumors arise in the ductal epithelium. Cytogenetic abnormalities and alterations in proliferation, oncogenes and tumor suppressor genes, cell receptors, and growth factors are described.

CONCLUSIONS

Preliminary studies have implicated, among others, the insulin-like growth factor-1 receptor, Src, and Stat3 proteins in human pancreatic carcinogenesis. These molecules may represent important predictors of tumor behavior and targets of novel therapeutic modalities in human pancreatic cancer.