The variable phenotype of the p.A16V mutation of cationic trypsinogen (PRSS1) in pancreatitis families

Genomic characteristics and immune landscape of super multiple primary lung cancer

BACKGROUND

In recent years, a growing number of patients with multiple primary lung cancer (MPLC) are being diagnosed, and a subset of these patients is found to have a large number of lesions at the time of diagnosis, which are referred to as 'super MPLC'.

METHODS

Here, we perform whole exome sequencing (WES) and immunohistochemistry (IHC) analysis of PD-L1 and CD8 on 212 tumor samples from 42 patients with super MPLC.

FINDINGS

We report the genomic alteration landscape of super MPLC. EGFR, RBM10 and TP53 mutation and TERT amplification are important molecular events in the evolution of super MPLC. We propose the conception of early intrapulmonary metastasis, which exhibits different clinical features from conventional metastasis. The IHC analyses of PD-L1 and CD8 reveal a less inflamed microenvironment of super MPLC than that of traditional non-small cell lung cancer (NSCLC). We identify the potentially susceptible germline mutations for super MPLC.

INTERPRETATION

Our study depicts the genomic characteristics and immune landscape, providing insights into the pathogenesis and possible therapeutic guidance of super MPLC.

FUNDING

A full list of funding bodies that supported this study can be found in the Acknowledgements section.

Managing complications of chronic pancreatitis: a guide for the gastroenterologist

INTRODUCTION

Chronic pancreatitis is a heterogeneous and complex syndrome that, in most cases, causes pain as a cardinal symptom and affects both the morphology and function of the pancreas, leading to several serious complications.

AREAS COVERED

The present review, based on a non-systematic PubMed search updated to June 2023, aims to present the current available evidence on the role of gastroenterologists in the diagnosis and treatment of both local and systemic complications by either endoscopic or medical treatments.

EXPERT OPINION

At diagnosis and during chronic pancreatitis follow-up, particular care is needed to consider not only the clinically manifest signs and symptoms of the disease, such as pain, jaundice, gastrointestinal obstruction, and pseudocysts, which require multidisciplinary discussion to establish the best treatment option (endoscopic or surgical), but also less evident systemic complications. Pancreatic exocrine and endocrine insufficiency, together with chronic inflammation, addiction, and dysbiosis, contribute to malnutrition, sarcopenia, and osteopathy. These complications, in turn, increase the risk of infection, thromboembolic events, and death. Patients with chronic pancreatitis also have an increased risk of psychiatric disorders and pancreatic cancer onset. Overall, patients with chronic pancreatitis should receive a holistic evaluation, considering all these aspects, possibly through multidisciplinary care in dedicated expert centers.

Genetic susceptibility to post-endoscopic retrograde cholangiopancreatography pancreatitis identified in propensity score-matched analysis

BACKGROUND/AIMS

A previous history of post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP) is a risk factor for PEP, suggesting that there may be a genetic predisposition to PEP. However, nothing is known about this yet. The aim of this study was to identify genetic variations associated with PEP.

METHODS

A cohort of high-risk PEP patients was queried from December 2016 to January 2019. For each PEP case, two propensity score-matched controls were selected. Whole exome sequencing was performed using blood samples. Genetic variants reported to be related to pancreatitis were identified. To discover genetic variants that predispose to PEP, a logistic regression analysis with clinical adjustment was performed. Gene-wise analyses were also conducted.

RESULTS

Totals of 25 PEP patients and 50 matched controls were enrolled. Among the genetic variants reported to be associated with pancreatitis, only CASR rs1042636 was identified, and it showed no significant difference between the case and control groups. A total of 54,269 non-synonymous variants from 14,313 genes was identified. Logistic regression analysis of these variants showed that the IRF2BP1 rs60158447 GC genotype was significantly associated with the occurrence of PEP (odds ratio 2.248, FDR q value = 0.005). Gene-wise analyses did not show any significant results.

CONCLUSION

This study found that the IRF2BP1 gene variant was significantly associated with PEP. This genetic variant is a highly targeted PEP risk factor candidate and can be used for screening high-risk PEP groups before ERCP through future validation. (ClinicalTrials.gov no. NCT02928718).

Classification of PRSS1 variants responsible for chronic pancreatitis: An expert perspective from the Franco-Chinese GREPAN study group

BACKGROUND

PRSS1 was the first reported chronic pancreatitis (CP) gene. The existence of both gain-of-function (GoF) and gain-of-proteotoxicity (GoP) pathological PRSS1 variants, together with the fact that PRSS1 variants have been identified in CP subtypes spanning the range from monogenic to multifactorial, has made the classification of PRSS1 variants very challenging.

METHODS

All currently reported PRSS1 variants (derived primarily from two databases) were manually reviewed with respect to their clinical genetics, functional analysis and population allele frequency. They were classified by variant type and pathological mechanism within the framework of our recently proposed ACMG/AMP guidelines-based seven-category system.

RESULTS

The total number of distinct germline PRSS1 variants included for analysis was 100, comprising 3 copy number variants (CNVs), 12 5' and 3' variants, 19 intronic variants, 5 nonsense variants, 1 frameshift deletion variant, 6 synonymous variants, 1 in-frame duplication, 3 gene conversions and 50 missense variants. Based upon a combination of clinical genetic and functional analysis, population data and in silico analysis, we classified 26 variants (all 3 CNVs, the in-frame duplication, all 3 gene conversions and 19 missense) as "pathogenic", 3 variants (missense) as "likely pathogenic", 5 variants (four missense and one promoter) as "predisposing", 13 variants (all missense) as "unknown significance", 2 variants (missense) as "likely benign", and all remaining 51 variants as "benign".

CONCLUSIONS

We describe an expert classification of the 100 PRSS1 variants reported to date. The results have immediate implications for reclassifying many ClinVar-registered PRSS1 variants as well as providing optimal guidelines/standards for reporting PRSS1 variants.

WITHDRAWN: Clinical interpretation of PRSS1 gene variants in patients with pancreatitis

The Publisher regrets that this article is an accidental duplication of an article that has already been published in Clinics and Research in Hepatology and Gastroenterology, Volume 45, Issue 1, 2021, 101497. https://doi.org/10.1016/j.clinre.2020.07.004. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal

Expanding ACMG variant classification guidelines into a general framework

BACKGROUND

The American College of Medical Genetics and Genomics (ACMG)-recommended five variant classification categories (pathogenic, likely pathogenic, uncertain significance, likely benign, and benign) have been widely used in medical genetics. However, these guidelines are fundamentally constrained in practice owing to their focus upon Mendelian disease genes and their dichotomous classification of variants as being either causal or not. Herein, we attempt to expand the ACMG guidelines into a general variant classification framework that takes into account not only the continuum of clinical phenotypes, but also the continuum of the variants' genetic effects, and the different pathological roles of the implicated genes.

MAIN BODY

As a disease model, we employed chronic pancreatitis (CP), which manifests clinically as a spectrum from monogenic to multifactorial. Bearing in mind that any general conceptual proposal should be based upon sound data, we focused our analysis on the four most extensively studied CP genes, PRSS1, CFTR, SPINK1 and CTRC. Based upon several cross-gene and cross-variant comparisons, we first assigned the different genes to two distinct categories in terms of disease causation: CP-causing (PRSS1 and SPINK1) and CP-predisposing (CFTR and CTRC). We then employed two new classificatory categories, "predisposing" and "likely predisposing", to replace ACMG's "pathogenic" and "likely pathogenic" categories in the context of CP-predisposing genes, thereby classifying all pathologically relevant variants in these genes as "predisposing". In the case of CP-causing genes, the two new classificatory categories served to extend the five ACMG categories whilst two thresholds (allele frequency and functional) were introduced to discriminate "pathogenic" from "predisposing" variants.

CONCLUSION

Employing CP as a disease model, we expand ACMG guidelines into a five-category classification system (predisposing, likely predisposing, uncertain significance, likely benign, and benign) and a seven-category classification system (pathogenic, likely pathogenic, predisposing, likely predisposing, uncertain significance, likely benign, and benign) in the context of disease-predisposing and disease-causing genes, respectively. Taken together, the two systems constitute a general variant classification framework that, in principle, should span the entire spectrum of variants in any disease-related gene. The maximal compliance of our five-category and seven-category classification systems with the ACMG guidelines ought to facilitate their practical application.

Does acute pancreatitis herald pancreatic ductal adenocarcinoma? A multicenter electronic health research network study

BACKGROUND AND OBJECTIVES

High mortality in pancreas ductal adenocarcinoma (PDAC) is related to delayed diagnosis and lack of cost-effective early detection strategies. Retrospective studies have demonstrated an association between PDAC and acute pancreatitis (AP). Herein, we explore the incidence of PDAC in patients with non-biliary and non-alcoholic AP.

METHODS

A population-based, retrospective cohort study was conducted utilizing TriNetX (Cambridge, MA). Patients ≥40 years with AP (ICD-10-CM code: K85) and without biliary AP (K85.1), alcohol-induced AP (K85.2) or chronic pancreatitis (K86.0, K86.1), were identified. The primary outcome was incidence of PDAC (C25) in patients at defined intervals following AP. We compared the rate of early-stage diagnosis (stage 1-2) and surgical resection among patients with and without preceding AP.

RESULTS

The incidence of PDAC ranged from 2.16% (1 year) to 3.43% (5 years). Patients with PDAC and AP in preceding year were more likely to undergo surgical resection relative to those without AP (10.1% vs. 6.3%, risk ratio 1.62: 95% confidence interval, CI 1.47-1.79). Early-stage diagnosis of PDAC was more frequent in patients with preceding AP; however, difference was insignificant (p = 0.48; 95% CI 0.64-2.58).

CONCLUSION

AP is infrequently associated with PDAC and can precede a diagnosis of PDAC in a minority of patients without another known etiology of pancreatitis. Patients with a recent AP are more likely to undergo surgical resection of PDAC and a trend toward diagnosis at an earlier stage compared to patients with PDAC and without AP. The impact of AP-related PDAC on survival is unknown.

Clinical interpretation of PRSS1 variants in patients with pancreatitis

Since the description of the PRSS1 gene encoding the cationic trypsinogen as being involved in dominant hereditary pancreatitis, more than 50 PRSS1 variants have been reported. Among the PRSS1 variants that have been classified as pathogenic, some have a high penetrance and others have a low penetrance. Assessing the clinical relevance of PRSS1 variants is often complicated in the absence of functional evidence and interpretation of rare variants is not very easy in clinical practice. The aim of this study was to review the different variants identified in the PRSS1 gene and to classify them according to their degree of deleterious effect. This classification was based on the results of several in vitro experiments and on population data, in comparing the allelic frequency of each variant in patients with pancreatitis and in unaffected individuals. This review should help geneticists and clinicians in charge of patient's care and genetic counseling to interpret molecular results.

International consensus guidelines on surveillance for pancreatic cancer in chronic pancreatitis. Recommendations from the working group for the international consensus guidelines for chronic pancreatitis in collaboration with the International Association of Pancreatology, the American Pancreatic Association, the Japan Pancreas Society, and European Pancreatic Club

BACKGROUND

Patients with chronic pancreatitis (CP) have an increased risk of pancreatic cancer. We present the international consensus guidelines for surveillance of pancreatic cancer in CP.

METHODS

The international group evaluated 10 statements generated from evidence on 5 questions relating to pancreatic cancer in CP. The GRADE approach was used to evaluate the level of evidence available per statement. The working group voted on each statement for strength of agreement, using a nine-point Likert scale in order to calculate Cronbach's alpha reliability coefficient.

RESULTS

In the following domains there was strong consensus: (1) the risk of pancreatic cancer in affected individuals with hereditary pancreatitis due to inherited PRSS1 mutations is high enough to justify surveillance; (2) the risk of pancreatic cancer in patients with CP associated with SPINK1 p. N34S is not high enough to justify surveillance; (3) surveillance should be undertaken in pancreatic specialist centers; (4) surveillance should only be introduced after the age of 40 years and stopped when the patient would no longer be suitable for surgical intervention. All patients with CP should be advised to lead a healthy lifestyle aimed at avoiding risk factors for progression of CP and pancreatic cancer. There was only moderate or weak agreement on the best methods of screening and surveillance in other types of environmental, familial and genetic forms of CP.

CONCLUSIONS

Patients with inherited PRSS1 mutations should undergo surveillance for pancreatic cancer, but the best methods for cancer detection need further investigation.

Early detection of pancreatic cancer

Pancreatic ductal adenocarcinoma is most frequently detected at an advanced stage. Such late detection restricts treatment options and contributes to a dismal 5-year survival rate of 3-15%. Pancreatic ductal adenocarcinoma is relatively uncommon and screening of the asymptomatic adult population is not feasible or recommended with current modalities. However, screening of individuals in high-risk groups is recommended. Here, we review groups at high risk for pancreatic ductal adenocarcinoma, including individuals with inherited predisposition and patients with pancreatic cystic lesions. We discuss studies aimed at finding ways of identifying pancreatic ductal adenocarcinoma in high-risk groups, such as among individuals with new-onset diabetes mellitus and people attending primary and secondary care practices with symptoms that suggest this cancer. We review early detection biomarkers, explore the potential of using social media for detection, appraise prediction models developed using electronic health records and research data, and examine the application of artificial intelligence to medical imaging for the purposes of early detection.

Early trypsin activation develops independently of autophagy in caerulein-induced pancreatitis in mice

Premature intrapancreatic trypsinogen activation is widely regarded as an initiating event for acute pancreatitis. Previous studies have alternatively implicated secretory vesicles, endosomes, lysosomes, or autophagosomes/autophagolysosomes as the primary site of trypsinogen activation, from which a cell-damaging proteolytic cascade originates. To identify the subcellular compartment of initial trypsinogen activation we performed a time-resolution analysis of the first 12 h of caerulein-induced pancreatitis in transgenic light chain 3 (LC3)-GFP autophagy reporter mice. Intrapancreatic trypsin activity increased within 60 min and serum amylase within 2 h, but fluorescent autophagosome formation only by 4 h of pancreatitis in parallel with a shift from cytosolic LC3-I to membranous LC3-II on Western blots. At 60 min, activated trypsin in heavier subcellular fractions was co-distributed with cathepsin B, but not with the autophagy markers LC3 or autophagy protein 16 (ATG16). Supramaximal caerulein stimulation of primary pancreatic acini derived from LC3-GFP mice revealed that trypsinogen activation is independent of autophagolysosome formation already during the first 15 min of exposure to caerulein. Co-localization studies (with GFP-LC3 autophagosomes versus Ile-Pro-Arg-AMC trypsin activity and immunogold-labelling of lysosomal-associated membrane protein 2 [LAMP-2] versus trypsinogen activation peptide [TAP]) indicated active trypsin in autophagolysosomes only at the later timepoints. In conclusion, during the initiating phase of caerulein-induced pancreatitis, premature protease activation develops independently of autophagolysosome formation and in vesicles arising from the secretory pathway. However, autophagy is likely to regulate overall intracellular trypsin activity during the later stages of this disease.

The Liverpool duodenum-and spleen-preserving near-total pancreatectomy can provide long-term pain relief in patients with end-stage chronic pancreatitis

PURPOSE

Total pancreatectomy may improve symptoms in patients with severe end-stage chronic pancreatitis. This might be achieved whilst preserving both the duodenum- and spleen-(DPSPTP). Mature clinical outcomes of this approach are presented.

METHODS

Single-centre prospective cohort study performed between September 1996 and May 2016. Demographic, clinical details, pain scores and employment status were prospectively recorded during clinic attendance.

RESULTS

Fifty-one patients (33 men, 18 women) with a median (interquartile range) age of 40.8 (35.3-49.4) years, a median weight of 69.8 (61.0-81.5) Kg and a median body mass index of 23.8 (21.5-27.8), underwent intended duodenum-and spleen-preserving near-total pancreatectomy for end-stage chronic pancreatitis. Aetiology was excess alcohol in 25, idiopathic (no mutation) in 15, idiopathic (SPINK-1/CFTR mutations) in two, hereditary (PRSS1 mutation) in seven and one each post-necrotising pancreatitis and obstructive pancreatic duct divisum in 1. The main indication for surgery was severe pain. Findings included parenchymal calcification in 79% and ductal calculi in 24%, a dilated main pancreatic duct in 57% and a dilated main bile duct in 17%, major vascular involvement in 27% and pancreato-peritoneal fistula in 2%. Postoperative complications occurred in 20 patients with two deaths. Median pain scores were 8 (7-8) preoperatively and 3 (0.25-5.75) at 5 years (p = 0.013). Opiate analgesic use was significantly reduced postoperatively (p = 0.048). Following surgery, 22 (63%) of 38 patients of working age re-entered employment compared with 12 (33%) working preoperatively (p = 0.016).

CONCLUSION

Duodenum-and spleen-preserving near-total pancreatectomy provided long-term relief in adult patients with intractable chronic pancreatitis pain, with improved employment prospects.

The diagnostic value of Rosemont and Japanese diagnostic criteria for 'indeterminate', 'suggestive', 'possible' and 'early' chronic pancreatitis

BACKGROUND

Longitudinal data are lacking to support consensus criteria for diagnosing early chronic pancreatitis.

METHODS

Retrospective single centre study of the initial evidence for chronic pancreatitis (CP), with reassessment after follow-up (January 2003-November 2016).

RESULTS

807 patients were previously diagnosed with chronic pancreatitis. This diagnosis was rejected in 118 patients: 52 had another pathology altogether, the remaining 66 patients formed the study population. 38 patients with 'normal' imaging were reclassified as chronic abdominal pain syndrome (CAPS), and 28 patients had minimal change features of CP on EUS (MCEUS) but never progressed. Strict application of the Japanese diagnostic criteria would diagnose only two patients with early CP and eleven as possible CP. Patients were more likely to have MCEUS if the EUS was performed within 12 months of an attack of acute pancreatitis. 40 patients with MCEUS were identified, including an additional 12 who progressed to definite CP after a median of 30 (18.75-36.5) months. Those continuing to consume excess alcohol and/or continued smoking were significantly more likely to progress. Those who progressed were more likely to develop pancreatic exocrine insufficiency, require pancreatic surgery and had higher mortality.

CONCLUSION

There needs to be more stringent application of the systems used for diagnosing chronic pancreatitis with revision of the current terminology 'indeterminate', 'suggestive', 'possible', and 'early' chronic pancreatitis. All patients with MCEUS features of CP require ongoing clinical follow up of at least 30 months and all patients with these features should be strongly counselled regarding smoking cessation and abstinence from alcohol.

CTRC gene polymorphism may increase pancreatic cancer risk – preliminary study

Pancreatic cancer is often fatal due to delayed diagnosis and treatment difficulties. Objective: To analyze selected SPINK1, CTRC, CFTR, and PRSS1 gene mutations in cancer tissue and blood samples of patients with pancreatic tumors. Materials and method: We enrolled 16 consecutive patients diagnosed with pancreatic tumors. We collected cancer tissue, normal pancreatic tissue, and blood samples for genetic tests. The control group consisted of 419 healthy individuals. Peripheral blood samples were collected from all study participants in EDTA-coated tubes. Results: Out of 16 patients with pancreatic tumors, 12 had pancreatic cancer on microscopic examination (mean age, 60.2 years). The CTRC polymorphism Hetero p.G60=(c.180C>T) was found in 5 patients with pancreatic cancer (41.7% vs. 18.6% in the control group). One patient with pancreatic cancer and a positive family history had the SPINK1 (p.N34S) mutation [8.3% vs. 2.9% (12/419) in the control group]. One patient with pancreatic cancer had the CTRC (p.R254W) mutation [8.3% vs. 1% (4/419) in the control group]. Conclusions: Our preliminary results show that the CTRC polymorphism p.G60= (c.180C>T) is frequent in patients with pancreatic cancer. However, further research is needed to verify our findings.

Chronic pancreatitis

Chronic pancreatitis is defined as a pathological fibro-inflammatory syndrome of the pancreas in individuals with genetic, environmental and/or other risk factors who develop persistent pathological responses to parenchymal injury or stress. Potential causes can include toxic factors (such as alcohol or smoking), metabolic abnormalities, idiopathic mechanisms, genetics, autoimmune responses and obstructive mechanisms. The pathophysiology of chronic pancreatitis is fairly complex and includes acinar cell injury, acinar stress responses, duct dysfunction, persistent or altered inflammation, and/or neuro-immune crosstalk, but these mechanisms are not completely understood. Chronic pancreatitis is characterized by ongoing inflammation of the pancreas that results in progressive loss of the endocrine and exocrine compartment owing to atrophy and/or replacement with fibrotic tissue. Functional consequences include recurrent or constant abdominal pain, diabetes mellitus (endocrine insufficiency) and maldigestion (exocrine insufficiency). Diagnosing early-stage chronic pancreatitis is challenging as changes are subtle, ill-defined and overlap those of other disorders. Later stages are characterized by variable fibrosis and calcification of the pancreatic parenchyma; dilatation, distortion and stricturing of the pancreatic ducts; pseudocysts; intrapancreatic bile duct stricturing; narrowing of the duodenum; and superior mesenteric, portal and/or splenic vein thrombosis. Treatment options comprise medical, radiological, endoscopic and surgical interventions, but evidence-based approaches are limited. This Primer highlights the major progress that has been made in understanding the pathophysiology, presentation, prevalence and management of chronic pancreatitis and its complications.

Genetic Risk in Chronic Pancreatitis: The Trypsin-Dependent Pathway

Genetic investigations have provided unique insight into the mechanism of chronic pancreatitis in humans and firmly established that uncontrolled trypsin activity is a central pathogenic factor. Mutations in the PRSS1, SPINK1, and CTRC genes promote increased activation of trypsinogen to trypsin by stimulation of autoactivation or by impairing protective trypsinogen degradation and/or trypsin inhibition. Here we review key genetic and biochemical features of the trypsin-dependent pathological pathway in chronic pancreatitis.

Hereditary pancreatitis of 3 Chinese children: Case report and literature review

BACKGROUND

Hereditary pancreatitis (HP) is quite rare and is distinguished by incomplete penetrance presentation as early-onset relapsing pancreatitis, usually beginning in childhood. HP is now known to be commonly relevant to mutations in the PRSS1 (gene-encoding cationic trypsinogen), SPINK1 (serine protease inhibitor, Kazal type 1), CFTR (cystic fibrosis), carboxypeptidase A1 (CPA1), and chymotrypsin C (CTRC) genes as reported in some Caucasian studies. HP has a variable spectrum of severity and may develop complications.

METHODS & RESULTS

We describe the clinical course of 3 preschool children, hospitalized with postprandial abdominal pain, whose laboratory tests showed high serum amylase. Similar episodes of abdominal pain led to readmission, and the patients recovered quickly after using symptomatic therapy. The condition of the first boy, who developed a pancreatic tail pseudocyst and splenic infarction, was especially complicated. The boy underwent 2 endoscopic retrograde cholangiopancreatographies and stenting, along with a surgical procedure that completely relieved his symptoms for 3 months. The 3 patients and their parents were given genetic testing. All of the patients carried 1 or more gene mutations inherited from their mothers, fathers, or both parents; however, none of the parents were affected.

CONCLUSION

For children with repeated pancreatitis, clinicians should consider HP in the differential diagnosis. It is reliable to perform gene sequencing on suspicious patients and their parents. Multidisciplinary and comprehensive treatment should be recommended to manage HP and its complications. Cholangiopancreatography and stenting is a relatively minimally invasive approach when compared with surgery and can be tried as an early intervention. Surgical procedures should be reserved for patients with complications.

Hereditary pancreatitis: current perspectives

Hereditary pancreatitis (HP) is a rare cause of acute, recurrent acute, and chronic pancreatitis. It may present similarly to other causes of acute and chronic pancreatitis, and often there has been a protracted evaluation prior to the diagnosis of HP. Since it was first described in 1952, multiple genetic defects that affect the action of digestive enzymes in the pancreas have been implicated. The most common mutations involve the PRSS1, CFTR, SPINK1, and CTRC genes. New mutations in these genes and previously unrecognized mutations in other genes are being discovered due to the increasing use of next-generation genomic sequencing. While the inheritance pathways of these genetic mutations may be variable and complex, sometimes involving coinheritance of other mutations, the clinical presentation of patients tends to be similar. Interactions with environmental triggers often play a role. Patients tend to present at an early age (prior to the second decade of life) and have a significantly increased risk for the development of pancreatic adenocarcinoma. Patients with HP may develop sequelae of chronic pancreatitis such as strictures and fluid collections as well as exocrine and endocrine insufficiency. Management of patients with HP involves avoidance of environmental triggers, surveillance for pancreatic adenocarcinoma, medical therapy for endocrine and exocrine insufficiency, pain management, and endoscopic or surgical treatment for complications. Care for affected patients should be individualized, with an emphasis on early diagnosis and multidisciplinary involvement to develop a comprehensive treatment strategy.

Is screening for pancreatic cancer in high-risk groups cost-effective? - Experience from a Danish national screening program

OBJECTIVE

Pancreatic cancer (PC) is the fourth leading cause of cancer death worldwide, symptoms are few and diffuse, and when the diagnosis has been made only 10-15% would benefit from resection. Surgery is the only potentially curable treatment for pancreatic cancer, and the prognosis seems to improve with early detection. A hereditary component has been identified in 1-10% of the PC cases. To comply with this, screening for PC in high-risk groups with a genetic disposition for PC has been recommended in research settings.

DESIGN

Between January 2006 and February 2014 31 patients with Hereditary pancreatitis or with a disposition of HP and 40 first-degree relatives of patients with Familial Pancreatic Cancer (FPC) were screened for development of Pancreatic Ductal Adenocarcinoma (PDAC) with yearly endoscopic ultrasound. The cost-effectiveness of screening in comparison with no-screening was assessed by the incremental cost-utility ratio (ICER).

RESULTS

By screening the FPC group we identified 2 patients with PDAC who were treated by total pancreatectomy. One patient is still alive, while the other died after 7 months due to cardiac surgery complications. Stratified analysis of patients with HP and FPC provided ICERs of 47,156 US$ vs. 35,493 US$ per life-year and 58,647 US$ vs. 47,867 US$ per QALY. Including only PDAC related death changed the ICER to 31,722 US$ per life-year and 42,128 US$ per QALY. The ICER for patients with FPC was estimated at 28,834 US$ per life-year and 38,785 US$ per QALY.

CONCLUSIONS

With a threshold value of 50,000 US$ per QALY this screening program appears to constitute a cost-effective intervention although screening of HP patients appears to be less cost-effective than FPC patients.

Molecular Biomarkers of Pancreatic Intraepithelial Neoplasia and Their Implications in Early Diagnosis and Therapeutic Intervention of Pancreatic Cancer

Lack of early detection and effective interventions is a major reason for the poor prognosis and dismal survival rates for pancreatic cancer. Pancreatic intraepithelial neoplasia (PanIN) is the most common precursor of invasive pancreatic ductal adenocarcinoma (PDAC). Each stage in the progression from PanIN to PDAC is well characterized by multiple significant genetic alterations affecting signaling pathways. Understanding the biological behavior and molecular alterations in the progression from PanIN to PDAC is crucial to the identification of noninvasive biomarkers for early detection and diagnosis and the development of preventive and therapeutic strategies for control of pancreatic cancer progression. This review focuses on molecular biomarkers of PanIN and their important roles in early detection and treatment of pancreatic cancer.

Incidence of post-ERCP pancreatitis from direct pancreatic juice collection in hereditary pancreatitis and familial pancreatic cancer before and after the introduction of prophylactic pancreatic stents and rectal diclofenac

OBJECTIVES

Individuals from hereditary pancreatitis (HP) and familial pancreatic cancer (FPC) kindreds are at increased risk of developing pancreatic cancer. Premalignant molecular changes may be detected in pancreatic juice collected by endoscopic retrograde cholangiopancreatography (ERCP). The objective was to determine the risk of post-ERCP pancreatitis (PEP).

METHODS

A prospective study (1999-2013) was undertaken of 80 ERCPs (24 in HP and 56 in FPC) from 60 individuals and the impact of PEP prophylaxis using a self-expelling pancreatic stent and 50 mg diclofenac per rectum from 2008.

RESULTS

There was no PEP in the HP cohort and 13 (23.2%) PEP from 56 procedures in the FPC cohort (P = 0.0077). Up to 2008 PEP had occurred in 7 (43.8%) of 16 procedures in FPC individuals versus none of 18 procedures in HP individuals (P = 0.0021). After the introduction of prophylaxis, the incidence of PEP fell to 6 (15.0%) of 40 procedures in FPC individuals (P = 0.0347).The odds ratio (95% confidence interval) was 0.23 (0.06-0.84) in favor of prophylaxis (0.035).

CONCLUSIONS

Individuals with HP are at minimal risk for PEP. Although the risk of PEP in individuals with FPC can be reduced by using prophylactic self-expelling stents and diclofenac, it remains too high for routine screening.

Genetics of pancreatitis: the 2014 update

Chronic pancreatitis is a progressive inflammatory disease in which pancreatic secretory parenchyma is destroyed and replaced by fibrous tissue, eventually leading to malnutrition and diabetes. Alcohol is the leading cause in Western countries, but genetic factors are also implicated. Since the identification of mutations in the cationic trypsinogen (PRSS1) gene as a cause of hereditary pancreatitis in 1996, we have seen great progress in our understanding of the genetics of pancreatitis. It has been established that mutations in the genes related to the activation and inactivation of trypsin(ogen) such as PRSS1, serine protease inhibitor Kazal type 1 (SPINK1) and chymotrypsin C (CTRC) genes are associated with pancreatitis. In 2013, carboxypeptidase A1 (CPA1) was identified as a novel pancreatitis susceptibility gene. Endoplasmic reticulum stress in pancreatic acinar cells resulting from the mis-folding of mutated pancreatic enzymes has been shown to act as a novel mechanism underlying the susceptibility to pancreatitis. In Japan, the nationwide survey revealed 171 patients (96 males and 75 females) with hereditary pancreatitis in 59 families based on the European Registry of Hereditary Pancreatitis and Familial Pancreatic Cancer criteria. 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. Next generation sequencers can perform billions of sequencing reactions with a read length of 150-250 nucleotides. Comprehensive analysis using next generation sequencers will be a promising strategy to identify novel pancreatitis-associated genes and further clarify the pathogenesis of pancreatitis.

Treatment options for chronic pancreatitis

This Review covers the latest developments in the treatment options for chronic pancreatitis. Pain is the most frequent and dominant symptom in patients with chronic pancreatitis, which ranges from severe disabling continuous pain to mild pain attacks and pain-free periods. Conventional treatment strategies and recent changes in the treatment of pain in patients with chronic pancreatitis are outlined. The different treatment options for pain consist of medical therapy, endoscopy or surgery. Their related merits and drawbacks are discussed. Finally, novel insights in the field of genetics and microbiota are summarized, and future perspectives are discussed.

Human cationic trypsinogen (PRSS1) variants and chronic pancreatitis

Variations in the serine protease 1 (PRSS1) gene encoding human cationic trypsinogen have been conclusively associated with autosomal dominant hereditary pancreatitis and sporadic nonalcoholic chronic pancreatitis. Most high-penetrance PRSS1 variants increase intrapancreatic trypsin activity by stimulating trypsinogen autoactivation and/or by inhibiting chymotrypsin C-dependent trypsinogen degradation. Alternatively, some PRSS1 variants can cause trypsinogen misfolding, which results in intracellular retention and degradation with consequent endoplasmic reticulum stress. However, not all PRSS1 variants are pathogenic, and clinical relevance of rare variants is often difficult to ascertain. Here we review the PRSS1 variants published since 1996 and discuss their functional properties and role in chronic pancreatitis.

Pancreatic cancer risk in hereditary pancreatitis

Inflammation is part of the body's immune response in order to remove harmful stimuli—like pathogens, irritants or damaged cells—and start the healing process. Recurrent or chronic inflammation on the other side seems a predisposing factor for carcinogenesis and has been found associated with cancer development. In chronic pancreatitis mutations of the cationic trypsinogen (PRSS1) gene have been identified as risk factors of the disease. Hereditary pancreatitis (HP) is a rare cause of chronic pancreatic inflammation with an early onset, mostly during childhood. HP often starts with recurrent episodes of acute pancreatitis and the clinical phenotype is not very much different from other etiologies of the disease. The long-lasting inflammation however generates a tumor promoting environment and represents a major risk factor for tumor development This review will reflect our knowledge concerning the specific risk of HP patients to develop pancreatic cancer.

Where genotype is not predictive of phenotype: towards an understanding of the molecular basis of reduced penetrance in human inherited disease

Some individuals with a particular disease-causing mutation or genotype fail to express most if not all features of the disease in question, a phenomenon that is known as 'reduced (or incomplete) penetrance'. Reduced penetrance is not uncommon; indeed, there are many known examples of 'disease-causing mutations' that fail to cause disease in at least a proportion of the individuals who carry them. Reduced penetrance may therefore explain not only why genetic diseases are occasionally transmitted through unaffected parents, but also why healthy individuals can harbour quite large numbers of potentially disadvantageous variants in their genomes without suffering any obvious ill effects. Reduced penetrance can be a function of the specific mutation(s) involved or of allele dosage. It may also result from differential allelic expression, copy number variation or the modulating influence of additional genetic variants in cis or in trans. The penetrance of some pathogenic genotypes is known to be age- and/or sex-dependent. Variable penetrance may also reflect the action of unlinked modifier genes, epigenetic changes or environmental factors. At least in some cases, complete penetrance appears to require the presence of one or more genetic variants at other loci. In this review, we summarize the evidence for reduced penetrance being a widespread phenomenon in human genetics and explore some of the molecular mechanisms that may help to explain this enigmatic characteristic of human inherited disease.

Long-range electrostatic complementarity governs substrate recognition by human chymotrypsin C, a key regulator of digestive enzyme activation

Human chymotrypsin C (CTRC) is a pancreatic serine protease that regulates activation and degradation of trypsinogens and procarboxypeptidases by targeting specific cleavage sites within their zymogen precursors. In cleaving these regulatory sites, which are characterized by multiple flanking acidic residues, CTRC shows substrate specificity that is distinct from that of other isoforms of chymotrypsin and elastase. Here, we report the first crystal structure of active CTRC, determined at 1.9-Å resolution, revealing the structural basis for binding specificity. The structure shows human CTRC bound to the small protein protease inhibitor eglin c, which binds in a substrate-like manner filling the S6-S5' subsites of the substrate binding cleft. Significant binding affinity derives from burial of preferred hydrophobic residues at the P1, P4, and P2' positions of CTRC, although acidic P2' residues can also be accommodated by formation of an interfacial salt bridge. Acidic residues may also be specifically accommodated in the P6 position. The most unique structural feature of CTRC is a ring of intense positive electrostatic surface potential surrounding the primarily hydrophobic substrate binding site. Our results indicate that long-range electrostatic attraction toward substrates of concentrated negative charge governs substrate discrimination, which explains CTRC selectivity in regulating active digestive enzyme levels.

New biomarkers and targets in pancreatic cancer and their application to treatment

Late diagnosis of pancreatic ductal adenocarcinoma (pancreatic cancer) and the limited response to current treatments results in an exceptionally poor prognosis. Advances in our understanding of the molecular events underpinning pancreatic cancer development and metastasis offer the hope of tangible benefits for patients. In-depth mutational analyses have shed light on the genetic abnormalities in pancreatic cancer, providing potential treatment targets. New biological studies in patients and in mouse models have advanced our knowledge of the timing of metastasis of pancreatic cancer, highlighting new directions for the way in which patients are treated. Furthermore, our increasing understanding of the molecular events in tumorigenesis is leading to the identification of biomarkers that enable us to predict response to treatment. A major drawback, however, is the general lack of an adequate systematic approach to advancing the use of biomarkers in cancer drug development, highlighted in a Cancer Biomarkers Collaborative consensus report. In this Review, we summarize the latest insights into the biology of pancreatic cancer, and their repercussions for treatment. We provide an overview of current treatments and, finally, we discuss novel therapeutic approaches, including the role of biomarkers in therapy for pancreatic cancer.

Genetics and pathogenesis of chronic pancreatitis: the 2012 update

Chronic pancreatitis is a persistent inflammation of the pancreas that results in irreversible morphological changes and impairment of both exocrine and endocrine functions. Genetic studies of the disease over the past 15 years have led to the identification of four firmly established susceptibility genes namely PRSS1, SPNIK1, CTRC and CFTR. Our previously published review (Chen and Férec. Annu Rev Genomics Hum Genet 2009) has comprehensively summarized the advances made in terms of genetics and pathogenesis of chronic pancreatitis, covering the data available up to early 2009. This review summarizes the important and representative findings published thereafter, focusing on (i) newly found disease-causing mutations, (ii) functional characterization of known variations and (iii) genotype and phenotype relationship.

Increased activation of hereditary pancreatitis-associated human cationic trypsinogen mutants in presence of chymotrypsin C

Mutations in human cationic trypsinogen (PRSS1) cause autosomal dominant hereditary pancreatitis. Increased intrapancreatic autoactivation of trypsinogen mutants has been hypothesized to initiate the disease. Autoactivation of cationic trypsinogen is proteolytically regulated by chymotrypsin C (CTRC), which mitigates the development of trypsin activity by promoting degradation of both trypsinogen and trypsin. Paradoxically, CTRC also increases the rate of autoactivation by processing the trypsinogen activation peptide to a shorter form. The aim of this study was to investigate the effect of CTRC on the autoactivation of clinically relevant trypsinogen mutants. We found that in the presence of CTRC, trypsinogen mutants associated with classic hereditary pancreatitis (N29I, N29T, V39A, R122C, and R122H) autoactivated at increased rates and reached markedly higher active trypsin levels compared with wild-type cationic trypsinogen. The A16V mutant, known for its variable disease penetrance, exhibited a smaller increase in autoactivation. The mechanistic basis of increased activation was mutation-specific and involved resistance to degradation (N29I, N29T, V39A, R122C, and R122H) and/or increased N-terminal processing by CTRC (A16V and N29I). These observations indicate that hereditary pancreatitis is caused by CTRC-dependent dysregulation of cationic trypsinogen autoactivation, which results in elevated trypsin levels in the pancreas.

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.

An overview of hereditary pancreatitis

Hereditary pancreatitis is a rare cause of chronic pancreatitis. The prevalence was evaluated to 0.3/100000 in Western Countries. Genetic disorders are due to mutations of the PRSS1 gene on the long arm of the chromosome 7, encoding for the cationic trypsinogen. The inheritance pattern is autosomal dominant with an incomplete penetrance (80%). Since 1996, more than 30 mutations were found. The three more common mutations are R122H, N29I and A16V. First symptoms begin since childhood, mainly before 10 years old. Main symptoms are pancreatic pain and acute pancreatitis (>70%). CP morphological changes as pancreatic calcifications are diagnosed at a median age of 22-25 years. Exocrine and endocrine pancreatic insufficiency occurred in 34% and 26% at a median age of 29 and 38 years. No clinical differences exist according to the mutation type. No excess of mortality in hereditary pancreatitis population compared to general population was found, despite a real risk of cancer. The cumulative risks of pancreatic cancer at 50, 60 and, 75 years are 10%, 18.7% and, 53.5%, respectively. The relative risk of cancer increases in smokers and is evaluated to 8.55. Hereditary pancreatitis diagnosis permits to propose an adapted management in expert centres.

The complex exocrine-endocrine relationship and secondary diabetes in exocrine pancreatic disorders

The pancreas is a dual organ with exocrine and endocrine functions. The interrelationship of the endocrine-exocrine parts of the pancreas is a complex one, but recent clinical and experimental studies have expanded our knowledge. Many disorders primarily of the exocrine pancreas, often solely in the clinical realm of gastroenterologists are associated with diabetes mellitus (DM). Although, the DM becoming disorders are often grouped with type 2 diabetes, the pathogenesis, clinical manifestations and management differ. We review here data on the association of exocrine-endocrine pancreas, the many hormones of the pancreas and their possible effects on the exocrine functions followed by data on the epidemiology, pathogenesis, and management of DM in chronic pancreatitis, cystic fibrosis, pancreatic cancer, and clinical states after pancreatic surgery.

Genetics of pancreatitis

PURPOSE OF REVIEW

Chronic pancreatitis is a syndrome characterized by chronic inflammation of the pancreas, with variable pain, calcifications, necrosis, fatty replacement, fibrosis and scarring and other complications. Disease susceptibility, severity, progression and pain patterns vary widely and do not necessarily parallel one another. Much of the variability in susceptibility to recurrent acute and chronic pancreatitis is now clearly shown to be related to genetic differences between patients. This review highlights recent advances and future directions in genetic research.

RECENT FINDINGS

The strongest risk factors are associated with genetic variations in PRSS1, SPINK1, CFTR, and to a lesser extent, CTRC and CASR. The latest research suggest that a single factor rarely causes pancreatitis, and the majority of patients with recurrent acute and chronic pancreatitis have multiple variants in a gene, or epistatic interactions between multiple genes, coupled with environmental stressors.

SUMMARY

Pancreatic diseases have a strong genetic component. Rather than a classic Mendelian disorder, recurrent acute and chronic pancreatitis represents truly complex diseases with the interaction and synergism of multiple genetic and environmental factors. The future will require new predictive models to guide prevention and therapy.

The prevalence of cationic trypsinogen (PRSS1) and serine protease inhibitor, Kazal type 1 (SPINK1) gene mutations in Polish patients with alcoholic and idiopathic chronic pancreatitis

BACKGROUND

The main cause of chronic pancreatitis (CP) is excessive alcohol consumption. On the other hand, only 5-10% of heavy drinkers develop chronic pancreatitis. We have only limited information regarding the pathogenic mechanism by which alcohol leads to the disease. Mutations of the PRSS1 and SPINK 1 have been mostly implicated in hereditary and idiopathic CP, but their presence in other types of this disease have also been reported.

AIMS

The aim of the study was to determine the frequency of PRSS1 and SPINK1 mutations in patients with chronic alcoholic (ACP) and idiopathic pancreatitis (ICP) as well as to investigate their relation to the clinical course of the disease.

METHODS

The study included 33 ACP and 14 ICP patients as well 46 healthy subjects. The diagnosis of CP was based on clinical data, ultrasound, and computed tomography. After isolation of DNA from peripheral blood two trypsinogen mutations were detected N29I and R122H by allelo-specific amplification polymerase chain reaction (ASA-PCR) and by the PCR-restriction fragment length polymorphism (RFLP). Beside this N34S mutation of SPINK1 was analyzed by PCR restriction fragment length polymorphism (PCR-RFLP).

RESULTS

PRSS1 mutations have been detected in 11 (33%) patients with ACP. The frequency of the PRSS1 mutations was higher in patients with ACP than in controls (4.3%) (p < 0.001). The frequency of PRSS1 mutation was present in 21.4% of ICP patients, which was significantly higher (p < 0.05) than in controls. Overall, six (18%) SPINK1 mutations in ACP group have been detected. Among 14 patients with ICP, in four (28.6%) of them SPINK1 has been detected. The same mutations have also been found in three (6.5%) control subjects. The frequency of the N34S mutation was higher in patients with ICP than in the controls (p < 0.05), but the frequency of N34S mutation did not differ between ACP and the control group. No relations have been detected between PRSS1 and SPINK1 mutations presence and clinical course and complications of CP.

CONCLUSIONS

Those preliminary data suggest the high prevalence of SPINK1 and PRSS1 mutations in the Polish population, generally, as well as in CP patients. It may be speculated that those mutations contribute to the development of chronic pancreatitis, especially in patients with alcohol overindulgence.