The P239S palladin variant does not account for a significant fraction of hereditary or early onset pancreas cancer

Germline Variants and Risk for Pancreatic Cancer: A Systematic Review and Emerging Concepts

Pancreatic cancer requires many genetic mutations. Combinations of underlying germline variants and environmental factors may increase the risk of cancer and accelerate the oncogenic process. We systematically reviewed, annotated, and classified previously reported pancreatic cancer-associated germline variants in established risk genes. Variants were scored using multiple criteria and binned by evidence for pathogenicity, then annotated with published functional studies and associated biological systems/pathways. Twenty-two previously identified pancreatic cancer risk genes and 337 germline variants were identified from 97 informative studies that met our inclusion criteria. Fifteen of these genes contained 66 variants predicted to be pathogenic (APC, ATM, BRCA1, BRCA2, CDKN2A, CFTR, CHEK2, MLH1, MSH2, NBN, PALB2, PALLD, PRSS1, SPINK1, TP53). Pancreatic cancer risk genes were organized into key biological mechanisms that promote pancreatic oncogenesis within an oncogenic model. Development of precision medicine approaches requires updated variant information within the framework of an oncogenic progression model. Complex risk modeling may improve interpretation of early biomarkers and guide pathway-specific treatment for pancreatic cancer in the future. Precision medicine is within reach.

Diagnosis and Management of Hereditary Pancreatic Cancer

Hereditary pancreatic cancer can be diagnosed through family history and/or a personal history of pancreatitis or clinical features suggesting one of the known pancreatic cancer predisposition syndromes. This chapter describes the currently known hereditary pancreatic cancer predisposition syndromes, including Peutz-Jeghers syndrome, familial atypical multiple mole melanoma, hereditary breast and ovarian cancer, Li-Fraumeni syndrome, hereditary non-polyposis colon cancer and familial adenomatous polyposis. Strategies for genetic testing for hereditary pancreatic cancer and the appropriate options for surveillance and cancer risk reduction are discussed. Finally, ongoing research and future directions in the diagnosis and management of hereditary pancreatic cancer will be considered.

Candidate DNA repair susceptibility genes identified by exome sequencing in high-risk pancreatic cancer

The genetic basis underlying the majority of hereditary pancreatic adenocarcinoma (PC) is unknown. Since DNA repair genes are widely implicated in gastrointestinal malignancies, including PC, we hypothesized that there are novel DNA repair PC susceptibility genes. As germline DNA repair gene mutations may lead to PC subtypes with selective therapeutic responses, we also hypothesized that there is an overall survival (OS) difference in mutation carriers versus non-carriers. We therefore interrogated the germline exomes of 109 high-risk PC cases for rare protein-truncating variants (PTVs) in 513 putative DNA repair genes. We identified PTVs in 41 novel genes among 36 kindred. Additional genetic evidence for causality was obtained for 17 genes, with FAN1, NEK1 and RHNO1 emerging as the strongest candidates. An OS difference was observed for carriers versus non-carriers of PTVs with early stage (≤IIB) disease. This adverse survival trend in carriers with early stage disease was also observed in an independent series of 130 PC cases. We identified candidate DNA repair PC susceptibility genes and suggest that carriers of a germline PTV in a DNA repair gene with early stage disease have worse survival.

A Systematic Comparison of Traditional and Multigene Panel Testing for Hereditary Breast and Ovarian Cancer Genes in More Than 1000 Patients

Gene panels for hereditary breast and ovarian cancer risk assessment are gaining acceptance, even though the clinical utility of these panels is not yet fully defined. Technical questions remain, however, about the performance and clinical interpretation of gene panels in comparison with traditional tests. We tested 1105 individuals using a 29-gene next-generation sequencing panel and observed 100% analytical concordance with traditional and reference data on >750 comparable variants. These 750 variants included technically challenging classes of sequence and copy number variation that together represent a significant fraction (13.4%) of the pathogenic variants observed. For BRCA1 and BRCA2, we also compared variant interpretations in traditional reports to those produced using only non-proprietary resources and following criteria based on recent (2015) guidelines. We observed 99.8% net report concordance, albeit with a slightly higher variant of uncertain significance rate. In 4.5% of BRCA-negative cases, we uncovered pathogenic variants in other genes, which appear clinically relevant. Previously unseen variants requiring interpretation accumulated rapidly, even after 1000 individuals had been tested. We conclude that next-generation sequencing panel testing can provide results highly comparable to traditional testing and can uncover potentially actionable findings that may be otherwise missed. Challenges remain for the broad adoption of panel tests, some of which will be addressed by the accumulation of large public databases of annotated clinical variants.

The current state of pancreatic cancer in Canada: incidence, mortality, and surgical therapy

OBJECTIVE

This study aimed to evaluate the trends in the incidence, survival, and surgical therapy for Canadian patients affected by pancreatic cancer (PC).

METHODS

The incidence, mortality, number of resections, and outcomes of patients with PC stratified by year, sex, and province were extracted from Canadian cancer databases.

RESULTS

In 2012, PC was diagnosed in 4600 Canadians and it was responsible for 4300 deaths. The age-standardized incidence was 9 to 10 new cases per 100,000 individuals. The mortality rate remained the highest among all the solid tumors with a case-to-fatality ratio of 0.93. The age-standardized 5-year relative survival was 9.1% (95% confidence interval [CI], 8.3-10). There were geographic variations among provinces with the highest survival registered in Ontario (10.9%; 95% CI, 9.9-12) and the lowest survival reported in Nova Scotia (4.7%; 95% CI, 2.8-7.2). The percentage of patients who underwent surgery decreased from 19% (2006-2007) to 17% (2009-2010). Pancreatic resections were performed in high-volume centers in 74% of cases. In-hospital mortality was 5%, 93% of patients were discharged home, and 36% of patients required home support after discharge.

CONCLUSIONS

Long-term outcomes of Canadian patients affected by PC remain unsatisfactory, with only 9% of the patients surviving at 5 years. Surgical therapy was performed only in 17% to 19% of patients.

Familial pancreatic cancer: current status

The term 'familial pancreatic cancer (FPC) defines families with at least two first-degree relatives with confirmed pancreatic cancer that do not fulfill the criteria of other inherited cancer syndromes with an increased risk for the development of PC, such as Peutz-Jeghers syndrome, hereditary pancreatitis and hereditary breast and ovarian cancer. FPC is a mostly autosomal dominant inherited tumor syndrome with a heterogeneous phenotype. The major genetic defect has not been identified yet, although mutations, for example in the BRCA2 gene, could be identified in some FPC families. Nevertheless, most experts recommend participation in screening and surveillance programs to high-risk individuals. Most board-approved screening programs are based on endoscopic ultrasound. The first data on the prospective screening of high-risk individuals have demonstrated that precursor lesions of PC can be identified, but false-positive findings do occur.

Pancreatic cancer screening

Accumulating data indicate that clinically available abdominal imaging tests such as EUS and MRI/MRCP can detect asymptomatic precursor benign (IPMN, PanIN) and invasive malignant pancreatic neoplasms, such as ductal adenocarcinoma, in individuals with an inherited predisposition. These asymptomatic FPCs detected have been more likely to be resectable, compared to symptomatic tumors. The most challenging part of screening high-risk individuals is the selection of individuals with high-grade precursor neoplasms for preventive treatment (ie, surgical resection before development of invasive cancer). Ongoing and future research should focus on formulating and validating a model for FPC risk and neoplastic progression using patient characteristics, imaging, and biomarkers. The comparative cost and effectiveness of various approaches for screening and surveillance of high-risk individuals also deserves study. For now, screening is best performed in high-risk individuals within the research protocols in academic centers with multidisciplinary teams with expertise in genetics, gastroenterology, radiology, surgery, and pathology.

The -409 C/T genotype of PRSS1 protects against pancreatic cancer in the Han Chinese population

BACKGROUND AND AIMS

The high mortality rate of pancreatic cancer is a bottleneck for further treatment with long-term efficacy. Thus, it is urgent to identify new methods to accurately predict the early onset of pancreatic cancer. We hypothesized that the different genotypes of cationic trypsinogen (PRSS1) gene could confer susceptibility and/or resistance to pancreatic cancer in the Han Chinese population.

METHODS

The genotypes of PRSS1 were determined in 154 patients with pancreatic cancer and in a control group of 520 healthy individuals of Han Chinese descent. Clinical information was obtained, single-nucleotide polymorphisms (SNPs) of the PRSS1 gene were analyzed by direct sequencing, and the distribution of the genotypes were tested for Hardy-Weinberg equilibrium. Odds ratios and 95% confidence intervals were calculated by logistic regression analysis to estimate the associations between the different genotypes or haplotypes and the risk of pancreatic cancer.

RESULTS

Three SNPs (-409 C/T, -204 A/C, and c.486 C/T) were identified. A case-control analysis revealed a 0.118-fold (95% CI: 0.037-0.653), 0.842-fold (95% CI: 0.177-4.010), and 0.750-fold (95% CI: 0.519-1.085) change in risk of developing pancreatic cancer for individuals harboring these SNPs, respectively. The individuals with the -409 C/T genotype tended to have a reduced risk compared to those who carried the -409 T/T genotype. A protective effect was observed for the C(-409)-A(-204)-C(486) haplotype compared to the T(-409)-A(-204)-T(486) haplotype (OR = 0.115, 95% CI: 0.016-0.849) or compared to the T(-409)-A(-204)-C(486) haplotype (OR = 0.090, 95% CI: 0.012-0.667). Serum levels of trypsin in patients with the -409 C/T genotype were only one-fourth that of those with the -409 T/T genotype and only one-third that of the healthy controls.

CONCLUSIONS

The -409 C/T genotype of PRSS1 was revealed to be a protective factor against pancreatic cancer in the Han Chinese population.

Arousal of cancer-associated stroma: overexpression of palladin activates fibroblasts to promote tumor invasion

Background

Cancer-associated fibroblasts, comprised of activated fibroblasts or myofibroblasts, are found in the stroma surrounding solid tumors. These myofibroblasts promote invasion and metastasis of cancer cells. Mechanisms regulating the activation of the fibroblasts and the initiation of invasive tumorigenesis are of great interest. Upregulation of the cytoskeletal protein, palladin, has been detected in the stromal myofibroblasts surrounding many solid cancers and in expression screens for genes involved in invasion. Using a pancreatic cancer model, we investigated the functional consequence of overexpression of exogenous palladin in normal fibroblasts in vitro and its effect on the early stages of tumor invasion.

Principal Findings

Palladin expression in stromal fibroblasts occurs very early in tumorigenesis. In vivo, concordant expression of palladin and the myofibroblast marker, alpha smooth muscle actin (α-SMA), occurs early at the dysplastic stages in peri-tumoral stroma and progressively increases in pancreatic tumorigenesis. In vitro introduction of exogenous 90 kD palladin into normal human dermal fibroblasts (HDFs) induces activation of stromal fibroblasts into myofibroblasts as marked by induction of α-SMA and vimentin, and through the physical change of cell morphology. Moreover, palladin expression in the fibroblasts enhances cellular migration, invasion through the extracellular matrix, and creation of tunnels through which cancer cells can follow. The fibroblast invasion and creation of tunnels results from the development of invadopodia-like cellular protrusions which express invadopodia proteins and proteolytic enzymes. Palladin expression in fibroblasts is triggered by the co-culture of normal fibroblasts with k-ras-expressing epithelial cells.

Conclusions

Overall, palladin expression can impart myofibroblast properties, in turn promoting the invasive potential of these peri-tumoral cells with invadopodia-driven degradation of extracellular matrix. Palladin expression in fibroblasts can be triggered by k-ras expression in adjacent epithelial cells. This data supports a model whereby palladin-activated fibroblasts facilitate stromal-dependent metastasis and outgrowth of tumorigenic epithelium.

The actin associated protein palladin in smooth muscle and in the development of diseases of the cardiovasculature and in cancer

Palladin is an actin associated protein serving as a cytoskeleton scaffold, and actin cross linker, localizing at stress fibers, focal adhesions, and other actin based structures. Recent studies showed that palladin plays a critical role in smooth muscle differentiation, migration, contraction, and more importantly contributes to embryonic development. This review will focus on the functions and possible mechanisms of palladin in smooth muscle and in pathological conditions such as cardiovascular diseases and cancers.

Precursor lesions of early onset pancreatic cancer

Early onset pancreatic cancer (EOPC) constitutes less than 5% of all newly diagnosed cases of pancreatic cancer (PC). Although histopathological characteristics of EOPC have been described, no detailed reports on precursor lesions of EOPC are available. In the present study, we aimed to describe histopathological picture of extratumoral parenchyma in 23 cases of EOPCs (definition based on the threshold value of 45 years of age) with particular emphasis on two types of precursor lesions of PC: pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasms (IPMNs). The types, grades, and densities of precursor lesions of PC were compared in patients with EOPCs, in young patients with neuroendocrine neoplasms (NENs), and in older (at the age of 46 or more) patients with PC. PanINs were found in 95.6% of cases of EOPCs. PanINs-3 were found in 39.1% of EOPC cases. Densities of all PanIN grades in EOPC cases were larger than in young patients with NENs. Density of PanINs-1A in EOPC cases was larger than in older patients with PC, but densities of PanINs of other grades were comparable. IPMN was found only in a single patient with EOPC but in 20% of older patients with PC. PanINs are the most prevalent precursor lesions of EOPC. IPMNs are rarely precursor lesions of EOPC. Relatively high density of low-grade PanINs-1 in extratumoral parenchyma of patients with EOPC may result from unknown multifocal genetic alterations in pancreatic tissue in patients with EOPCs.

Advances in diagnosis, treatment and palliation of pancreatic carcinoma: 1990-2010

Several advances in genetics, diagnosis and palliation of pancreatic cancer (PC) have occurred in the last decades. A multidisciplinary approach to this disease is therefore recommended. PC is relatively common as it is the fourth leading cause of cancer related mortality. Most patients present with obstructive jaundice, epigastric or back pain, weight loss and anorexia. Despite improvements in diagnostic modalities, the majority of cases are still detected in advanced stages. The only curative treatment for PC remains surgical resection. No more than 20% of patients are candidates for surgery at the time of diagnosis and survival remains quite poor as adjuvant therapies are not very effective. A small percentage of patients with borderline non-resectable PC might benefit from neo-adjuvant chemoradiation therapy enabling them to undergo resection; however, randomized controlled studies are needed to prove the benefits of this strategy. Patients with unresectable PC benefit from palliative interventions such as biliary decompression and celiac plexus block. Further clinical trials to evaluate new chemo and radiation protocols as well as identification of genetic markers for PC are needed to improve the overall survival of patients affected by PC, as the current overall 5-year survival rate of patients affected by PC is still less than 5%. The aim of this article is to review the most recent high quality literature on this topic.

Upper gastrointestinal cancer predisposition syndromes

Malignancies of the upper gastrointestinal tract form a heterogeneous group of cancers characterized by unique epidemiology and biology. Despite these differences, survival for advanced disease remains poor across the panel of diseases, from cancers of the esophagus, stomach, pancreas, and, until recently, even gastrointestinal stromal tumors. Genetic predisposition syndromes associated with these diseases comprise an emerging subset of these diseases that may provide valuable information on cause and etiology. They may provide insight into molecular drivers for the disease, or disease subtypes, and also insights into novel gene/environment interactions. This review summarizes the current understanding of genetic predisposition syndromes of cancers of the upper gastrointestinal tract.

Current status of molecular markers for early detection of sporadic pancreatic cancer

Pancreatic cancer (PC) is a highly lethal malignancy with near 100% mortality. This is in part due to the fact that most patients present with metastatic or locally advanced disease at the time of diagnosis. Significantly, in nearly 95% of PC patients there is neither an associated family history of PC nor of diseases known to be associated with an increased risk of PC. These groups of patients who comprise the bulk of PC cases are termed as "sporadic PC" in contrast to the familial PC cases that comprise only about 5% of all PCs. Given the insidious onset of the malignancy and its extreme resistance to chemo and radiotherapy, an abundance of research in recent years has focused on identifying biomarkers for the early detection of PC, specifically aiming at the sporadic PC cohort. However, while several studies have established that asymptomatic individuals with a positive family history of PC and those with certain heritable syndromes are candidates for PC screening, the role of screening in identifying sporadic PC is still an unsettled question. The present review attempts to assess this critical question by investigating the recent advances made in molecular markers with potential use in the early diagnosis of sporadic PC - the largest cohort of PC cases worldwide. It also outlines a novel yet simple risk factor based stratification system that could be potentially employed by clinicians to identify those individuals who are at an elevated risk for the development of sporadic PC and therefore candidates for screening.

Actinin-4 expression in primary and metastasized pancreatic ductal adenocarcinoma

OBJECTIVES

Actinin-4 is an actin-bundling protein that probably has a tumor-promoting potential in several solid tumors. The present study analyzed the expression of actinin-4 in the pancreas, in localized and metastasized pancreatic ductal adenocarcinoma (PDAC), and the correlation with clinical outcome.

METHODS

Pancreatic ductal adenocarcinoma tissue from 38 patients, 15 lymph node and 10 liver metastases, normal pancreas, and 4 PDAC cell lines, were examined by immunohistochemistry, and actinin-4 expression was quantified by immunofluorescence analysis.

RESULTS

In the normal pancreas, actinin-4 was most prominently expressed in ductal cells. In PDAC, tumor cells exhibited strong but differential cytoplasmic immunoreactivity for actinin-4. A multivariate analysis revealed actinin-4 immunoreactivity, advanced age, and undifferentiated grade as significant prognostic factors associated with worse survival after PDAC resection. Cells metastasized to lymph nodes or to the liver exhibited no significant increase of actinin-4 compared with the primary tumors. A nuclear staining was observed neither in any of the PDAC samples nor in the 4 cell lines. In PDAC cells, actinin-4 localized to dynamic actin structures and to invadopodia.

CONCLUSIONS

Actinin-4 expression levels significantly correlate with worse survival after PDAC resection. Although actinin-4 has been reported to promote lymph node metastases, there was no enhanced expression in PDAC metastases.

Cytoplasmic Ig-domain proteins: cytoskeletal regulators with a role in human disease

Immunoglobulin domains are found in a wide variety of functionally diverse transmembrane proteins, and also in a smaller number of cytoplasmic proteins. Members of this latter group are usually associated with the actin cytoskeleton, and most of them bind directly to either actin or myosin, or both. Recently, studies of inherited human disorders have identified disease-causing mutations in five cytoplasmic Ig-domain proteins: myosin-binding protein C, titin, myotilin, palladin, and myopalladin. Together with results obtained from cultured cells and mouse models, these clinical studies have yielded novel insights into the unexpected roles of Ig domain proteins in mechanotransduction and signaling to the nucleus. An emerging theme in this field is that cytoskeleton-associated Ig domain proteins are more than structural elements of the cell, and may have evolved to fill different needs in different cellular compartments. Cell Motil. Cytoskeleton 2009. (c) 2009 Wiley-Liss, Inc.

Binding of pro-prion to filamin A disrupts cytoskeleton and correlates with poor prognosis in pancreatic cancer

The cellular prion protein (PrP) is a highly conserved, widely expressed, glycosylphosphatidylinositol-anchored (GPI-anchored) cell surface glycoprotein. Since its discovery, most studies on PrP have focused on its role in neurodegenerative prion diseases, whereas its function outside the nervous system remains unclear. Here, we report that human pancreatic ductal adenocarcinoma (PDAC) cell lines expressed PrP. However, the PrP was neither glycosylated nor GPI-anchored, existing as pro-PrP and retaining its GPI anchor peptide signal sequence (GPI-PSS). We also showed that the PrP GPI-PSS has a filamin A-binding (FLNa-binding) motif and interacted with FLNa, an actin-associated protein that integrates cell mechanics and signaling. Binding of pro-PrP to FLNa disrupted cytoskeletal organization. Inhibition of PrP expression by shRNA in the PDAC cell lines altered the cytoskeleton and expression of multiple signaling proteins; it also reduced cellular proliferation and invasiveness in vitro as well as tumor growth in vivo. A subgroup of human patients with pancreatic cancer was found to have tumors that expressed pro-PrP. Most importantly, PrP expression in tumors correlated with a marked decrease in patient survival. We propose that binding of pro-PrP to FLNa perturbs FLNa function, thus contributing to the aggressiveness of PDAC. Prevention of this interaction could provide an attractive target for therapeutic intervention in human PDAC.

Absence of deleterious palladin mutations in patients with familial pancreatic cancer

It has been reported that germline mutations in the palladin gene (PALLD) cause the familial aggregation of pancreatic cancer, but the evidence is weak and controversial. We sequenced the coding regions of PALLD in 48 individuals with familial pancreatic cancer. We did not find any deleterious mutations and find no evidence to implicate mutations in PALLD as a cause of familial pancreatic cancer.

Familial pancreatic cancer

CONTEXT

Approximately 5% to 10% of individuals with pancreatic cancer report a history of pancreatic cancer in a close family member. In addition, several known genetic syndromes, such as familial breast cancer (BRCA2), the Peutz-Jeghers syndrome, and the familial atypical multiple mole melanoma syndrome, have been shown to be associated with an increased risk of pancreatic cancer. The known genes associated with these conditions can explain only a portion of the clustering of pancreatic cancer in families, and research to identify additional susceptibility genes is ongoing.

OBJECTIVE

To provide an understanding of familial pancreatic cancer and the pathology of familial exocrine pancreatic cancers.

DATA SOURCES

Published literature on familial aggregation of pancreatic cancer and familial exocrine pancreatic tumors.

CONCLUSIONS

Even in the absence of predictive genetic testing, the collection of a careful, detailed family history is an important step in the management of all patients with pancreatic cancer. While most pancreatic cancers that arise in patients with a family history are ductal adenocarcinomas, certain subtypes of pancreatic cancer have been associated with familial syndromes. Therefore, the histologic appearance of the pancreatic cancer itself, and/or the presence and appearance of precancerous changes in the pancreas, may increase the clinical index of suspicion for a genetic syndrome.

Familial pancreatic cancer

CONTEXT

Approximately 5% to 10% of individuals with pancreatic cancer report a history of pancreatic cancer in a close family member. In addition, several known genetic syndromes, such as familial breast cancer (BRCA2), the Peutz-Jeghers syndrome, and the familial atypical multiple mole melanoma syndrome, have been shown to be associated with an increased risk of pancreatic cancer. The known genes associated with these conditions can explain only a portion of the clustering of pancreatic cancer in families, and research to identify additional susceptibility genes is ongoing.

OBJECTIVE

To provide an understanding of familial pancreatic cancer and the pathology of familial exocrine pancreatic cancers.

DATA SOURCES

Published literature on familial aggregation of pancreatic cancer and familial exocrine pancreatic tumors.

CONCLUSIONS

Even in the absence of predictive genetic testing, the collection of a careful, detailed family history is an important step in the management of all patients with pancreatic cancer. While most pancreatic cancers that arise in patients with a family history are ductal adenocarcinomas, certain subtypes of pancreatic cancer have been associated with familial syndromes. Therefore, the histologic appearance of the pancreatic cancer itself, and/or the presence and appearance of precancerous changes in the pancreas, may increase the clinical index of suspicion for a genetic syndrome.

Screening for pancreatic cancer in high-risk individuals: a call for endoscopic ultrasound

Pancreatic cancer has a dismal prognosis, and early detection through screening is likely to be our best hope to improve survival. The relatively low incidence of pancreatic cancer and the insensitive screening techniques available currently render this approach prohibitively expensive and inefficient in the general population. Screening has begun, however, in the subset of patients at the highest risk of disease, such as those with inherited risk due to familial multiorgan cancer syndromes or in familial groupings of pancreatic cancer with yet unidentified genetic abnormalities, termed familial pancreatic cancer. Screening is currently done at several large centers in the world, each with a unique multidisciplinary approach and series of screening tests. Endoscopic ultrasound has emerged as the most promising imaging test given its high sensitivity and potential for tissue sampling. However, this potential to detect and cure early lesions should be carefully balanced with the risk of overtreatment, especially in view of the morbidity and mortality of pancreatic surgery. Additional experience to help determine the best screening strategy is greatly needed. Screening should therefore be done at experienced centers with multidisciplinary teams of specialists and in the context of research protocols.

Genetic predisposition and environmental risk factors to pancreatic cancer: A review of the literature

Some cases of pancreatic cancer (PC) are described to cluster within families. With the exception of PALLD gene mutations, which explain only a very modest fraction of familial cases, the genetic basis of familial PC is still obscure. Here the literature was reviewed in order to list the known genes, environmental factors, and health conditions associated with PC or involved in the carcinogenesis of the pancreas. Most of the genes listed are responsible for various well-defined cancer syndromes, such as CDKN2A (familial atypical mole-multiple melanoma, FAMMM), the mismatch repair genes (Lynch Syndrome), TP53 (Li-Fraumeni syndrome), APC (familial adenomatous polyposis), and BRCA2 (breast-ovarian familial cancer), where PC is part of the cancer spectrum of the disease. In addition, in this review I ranked known/possible risk factors extending the analysis to the hereditary pancreatitis (HP), diabetes, or to specific environmental exposures such as smoking. It appears that these factors contribute strongly to only a small proportion of PC cases. Recent work has revealed new genes somatically mutated in PC, including alterations within the pathways of Wnt/Notch and DNA mismatch repair. These new insights will help to reveal new candidate genes for the susceptibility to this disease and to better ascertain the actual contribution of the familial forms.

[Hereditary pancreatic cancer]

An inherited predisposition to pancreatic cancer (PC) is prevalent in about 3% of PC cases and is currently believed to occur in three distinct clinical settings, (1) hereditary tumour predisposition syndromes with an increased risk of PC such as Peutz-Jeghers syndrome and familial atypical multiple mole melanoma, (2) hereditary pancreatitis and cystic fibrosis, in which genetically determined early-age changes of the pancreas can predispose to the development of PC, and (3) familial pancreatic cancer syndrome (FPC). According to a recent consensus conference, high-risk individuals from PC-prone families should be enrolled in board-approved, prospective, controlled screening programs at expert centres. Based on the available data, prophylactic pancreatectomy is not indicated, since the underlying causative gene defect of the FPC syndrome is still unknown and the penetrance of PC in other tumour predisposition syndromes is either low or yet undetermined. In case of the diagnosis of a PC or high-grade precursor lesions, a prophylactic extension of the resection can be considered, since patients with hereditary PC often develop multifocal pancreatic lesions.

Screening and surveillance approaches in familial pancreatic cancer

Screening and surveillance for pancreatic cancer and its precursors is a relatively new indication for endoscopic ultrasound. It provides an alternative approach to the ineffective treatment of mostly incurable symptomatic pancreatic cancer. It is currently reserved for individuals with an increased risk for pancreatic ductal adenocarcinoma, such as those who have inherited genetic syndromes (eg, patients who have Peutz-Jeghers syndrome or hereditary pancreatitis, germline mutation carriers of p16 and BRCA2) and at-risk relatives of patients who have familial pancreatic cancer. This article discusses the rationale for performing screening and surveillance, the types of patients who are eligible for screening, the diagnostic modalities and technique for screening, the diagnostic yield of screening, and the ongoing research.

Genetic susceptibility in pancreatic ductal adenocarcinoma

BACKGROUND

The strongest risk factors for pancreatic adenocarcinoma are tobacco smoking and increasing age. However, only a few smokers or elderly individuals develop the disease and genetic factors are also likely to be important.

METHODS

The literature on genetic factors modifying susceptibility to cancer was reviewed, with particular regard to the interindividual variation that exists in the development of pancreatic adenocarcinoma.

RESULTS

Tobacco-derived carcinogen-metabolizing enzyme gene variants have been the main area of study in stratifying the risk of sporadic pancreatic cancer. Inconsistent results have emerged from the few molecular epidemiological studies performed.

CONCLUSION

There is great scope for further investigation of critical pathways and unidentified genetic influences may be revealed. This may eventually allow the identification of individuals at high risk who might be targeted for screening.

Familial pancreatic cancer: from genes to improved patient care

Pancreatic cancer is essentially a disease caused by inherited and acquired mutations in cancer-causing genes. A number of the genes responsible for the aggregation of pancreatic cancer in families have been discovered, including BRCA2, p16/CDKN2A, STK11 and PRSS1. Individuals can be tested for germline mutations in these genes; however, until recently, little could be done about the risk of pancreatic cancer if a patient was found to carry a mutation. Currently, new approaches are being developed to screen at-risk individuals for curable precancerous pancreatic lesions and laboratory studies have led to novel therapies that specifically target some of these genetic defects. This review focuses on the genetic basis for the familial aggregation of pancreatic cancer, with emphasis placed on the implications of the genetic alterations on clinical patient care.

Proteomics studies of pancreatic cancer

Pancreatic cancer is the fourth leading cause of cancer death in the United States, with 4% survival 5 years after diagnosis. Biomarkers are desperately needed to improve earlier, more curable cancer diagnosis and to develop new effective therapeutic targets. The development of quantitative proteomics technologies in recent years offers great promise for understanding the complex molecular events of tumorigenesis at the protein level, and has stimulated great interest in applying the technology for pancreatic cancer studies. Proteomic studies of pancreatic tissues, juice, serum/plasma, and cell lines have recently attempted to identify differentially expressed proteins in pancreatic cancer to dissect the abnormal signaling pathways underlying oncogenesis, and to detect new biomarkers. It can be expected that the continuing evolution of proteomics technology with better resolution and sensitivity will greatly enhance our capability in combating pancreatic cancer.