Long or short? Telomere length and pancreatic cancer and its precursor lesions, a narrative review.

Pancreatic ductal adenocarcinoma (PDAC) is the most common and lethal form of pancreatic cancer, with a survival approaching only 11% at five years after diagnosis. In the last 15 years, telomere length measured in leukocyte (LTL) has been studied in relation to PDAC risk. The majority of the studies reported an association between short LTL and increased PDAC risk, but the results are heterogeneous. Genome-wide association studies have identified several single nucleotide polymorphisms (SNPs) in the telomerase reverse transcriptase (TERT) gene as susceptibility loci for PDAC. Polygenic risk scores (PRS) computed using SNPs associated with LTL have been tested in relation to PDAC susceptibility with various methods and giving contrasting results. The aim of this review is to analyze all publications carried out specifically on LTL, considering LTL measured with qPCR and with genetic proxies, and PDAC risk. Additionally, we will give an overview of the most relevant associations between SNPs in telomere associated genes and PDAC, to answer the question shorter or longer? Which one of the two is associated with PDAC risk?

Role of pancreatic ductal adenocarcinoma risk factors in intraductal papillary mucinous neoplasm progression.

Introduction: Pancreatic ductal adenocarcinoma (PDAC) is lethal due to its late diagnosis and lack of successful treatments. A possible strategy to reduce its death burden is prevention. Intraductal papillary mucinous neoplasms (IPMNs) are precursors of PDAC. It is difficult to estimate the incidence of IPMNs because they are asymptomatic. Two recent studies reported pancreatic cysts in 3% and 13% of scanned subjects. The possibility of identifying a subgroup of IPMN patients with a higher probability of progression into cancer could be instrumental in increasing the survival rate. In this study, genetic and non-genetic PDAC risk factors were tested in a group of IPMN patients under surveillance. Methods: A retrospective study was conducted on 354 IPMN patients enrolled in two Italian centres with an average follow-up of 64 months. With the use of DNA extracted from blood, collected at IPMN diagnosis, all patients were genotyped for 30 known PDAC risk loci. The polymorphisms were analysed individually and grouped in an unweighted polygenic score (PGS) in relation to IPMN progression. The ABO blood group and non-genetic PDAC risk factors were also analysed. IPMN progression was defined based on the development of worrisome features and/or high-risk stigmata during follow-up. Results: Two genetic variants (rs1517037 and rs10094872) showed suggestive associations with an increment of IPMN progression. After correction for multiple testing, using the Bonferroni correction, none of the variants showed a statistically significant association. However, associations were observed for the non-genetic variables, such as smoking status, comparing heavy smokers with light smokers (HR = 3.81, 95% 1.43-10.09, p = 0.007), and obesity (HR = 2.46, 95% CI 1.22-4.95, p = 0.012). Conclusion: In conclusion, this study is the first attempt to investigate the presence of shared genetic background between PDAC risk and IPMN progression; however, the results suggest that the 30 established PDAC susceptibility polymorphisms are not associated with clinical IPMN progression in a sample of 354 patients. However, we observed indications of cigarette smoking and body mass index (BMI) involvement in IPMN progression. The biological mechanism that could link these two risk factors to progression could be chronic inflammation, of which both smoking and obesity are strong promoters.

Polymorphic variants involved in methylation regulation: a strategy to discover risk loci for pancreatic ductal adenocarcinoma.

INTRODUCTION: Only a small number of risk factors for pancreatic ductal adenocarcinoma (PDAC) has been established. Several studies identified a role of epigenetics and of deregulation of DNA methylation. DNA methylation is variable across a lifetime and in different tissues; nevertheless, its levels can be regulated by genetic variants like methylation quantitative trait loci (mQTLs), which can be used as a surrogate. MATERIALS AND METHODS: We scanned the whole genome for mQTLs and performed an association study in 14 705 PDAC cases and 246 921 controls. The methylation data were obtained from whole blood and pancreatic cancer tissue through online databases. We used the Pancreatic Cancer Cohort Consortium and the Pancreatic Cancer Case-Control Consortium genome-wide association study (GWAS) data as discovery phase and the Pancreatic Disease Research consortium, the FinnGen project and the Japan Pancreatic Cancer Research consortium GWAS as replication phase. RESULTS: The C allele of 15q26.1-rs12905855 showed an association with a decreased risk of PDAC (OR=0.90, 95% CI 0.87 to 0.94, p=4.93×10-8 in the overall meta-analysis), reaching genome-level statistical significance. 15q26.1-rs12905855 decreases the methylation of a 'C-phosphate-G' (CpG) site located in the promoter region of the RCCD1 antisense (RCCD1-AS1) gene which, when expressed, decreases the expression of the RCC1 domain-containing (RCCD1) gene (part of a histone demethylase complex). Thus, it is possible that the rs12905855 C-allele has a protective role in PDAC development through an increase of RCCD1 gene expression, made possible by the inactivity of RCCD1-AS1. CONCLUSION: We identified a novel PDAC risk locus which modulates cancer risk by controlling gene expression through DNA methylation.

A polymorphic variant in telomere maintenance is associated with worrisome features and high-risk stigmata development in IPMNs.

Intraductal papillary mucinous neoplasms (IPMNs) are nonobligatory precursor lesions of pancreatic ductal adenocarcinoma (PDAC). The identification of molecular biomarkers able to predict the risk of progression of IPMNs toward malignancy is largely lacking and sorely needed. Telomere length (TL) is associated with the susceptibility of developing cancers, including PDAC. Moreover, several PDAC risk factors have been shown to be associated with IPMN transition to malignancy. TL is genetically determined, and the aim of this study was to use 11 SNPs, alone or combined in a score (teloscore), to estimate the causal relation between genetically determined TL and IPMNs progression. For this purpose, 173 IPMN patients under surveillance were investigated. The teloscore did not show any correlation, however, we observed an association between PXK-rs6772228-A and an increased risk of IPMN transition to malignancy (HR = 3.17; 95%CI 1.47-6.84; P = 3.24 × 10-3). This effect was also observed in a validation cohort of 142 IPMNs even though the association was not statistically significant. The combined analysis was consistent showing an association between PXK-rs6772228-A and increased risk of progression. The A allele of this SNP is strongly associated with shorter LTL that in turn have been reported to be associated with increased risk of developing PDAC. These results clearly highlight the importance of looking for genetic variants as potential biomarkers in this setting in order to further our understanding the etiopathogenesis of PDAC and suggest that genetically determined TL might be an additional marker of IPMN prognosis.

Association of Genetic Variants Affecting microRNAs and Pancreatic Cancer Risk.

Genetic factors play an important role in the susceptibility to pancreatic cancer (PC). However, established loci explain a small proportion of genetic heritability for PC; therefore, more progress is needed to find the missing ones. We aimed at identifying single nucleotide polymorphisms (SNPs) affecting PC risk through effects on micro-RNA (miRNA) function. We searched in silico the genome for SNPs in miRNA seed sequences or 3 prime untranslated regions (3'UTRs) of miRNA target genes. Genome-wide association data of PC cases and controls from the Pancreatic Cancer Cohort (PanScan) Consortium and the Pancreatic Cancer Case-Control (PanC4) Consortium were re-analyzed for discovery, and genotyping data from two additional consortia (PanGenEU and PANDoRA) were used for replication, for a total of 14,062 cases and 11,261 controls. None of the SNPs reached genome-wide significance in the meta-analysis, but for three of them the associations were in the same direction in all the study populations and showed lower value of p in the meta-analyses than in the discovery phase. Specifically, rs7985480 was consistently associated with PC risk (OR = 1.12, 95% CI 1.07-1.17, p = 3.03 × 10-6 in the meta-analysis). This SNP is in linkage disequilibrium (LD) with rs2274048, which modulates binding of various miRNAs to the 3'UTR of UCHL3, a gene involved in PC progression. In conclusion, our results expand the knowledge of the genetic PC risk through miRNA-related SNPs and show the usefulness of functional prioritization to identify genetic polymorphisms associated with PC risk.

Lack of association of CD44-rs353630 and CHI3L2-rs684559 with pancreatic ductal adenocarcinoma survival.

Although pancreatic ductal adenocarcinoma (PDAC) survival is poor, there are differences in patients' response to the treatments. Detection of predictive biomarkers explaining these differences is of the utmost importance. In a recent study two genetic markers (CD44-rs353630 and CHI3L2-rs684559) were reported to be associated with survival after PDAC resection. We attempted to replicate the associations in 1856 PDAC patients (685 resected with stage I/II) from the PANcreatic Disease ReseArch (PANDoRA) consortium. We also analysed the combined effect of the two genotypes in order to compare our results with what was previously reported. Additional stratified analyses considering TNM stage of the disease and whether the patients received surgery were also performed. We observed no statistically significant associations, except for the heterozygous carriers of CD44-rs353630, who were associated with worse OS (HR = 5.01; 95% CI 1.58-15.88; p = 0.006) among patients with stage I disease. This association is in the opposite direction of those reported previously, suggesting that data obtained in such small subgroups are hardly replicable and should be considered cautiously. The two polymorphisms combined did not show any statistically significant association. Our results suggest that the effect of CD44-rs353630 and CHI3L2-rs684559 cannot be generalized to all PDAC patients.

Genome-wide scan of long noncoding RNA single nucleotide polymorphisms and pancreatic cancer susceptibility.

Pancreatic ductal adenocarcinoma (PDAC) is projected to become the second cancer-related cause of death by 2030. Identifying novel risk factors, including genetic risk loci, could be instrumental in risk stratification and implementation of prevention strategies. Long noncoding RNAs (lncRNAs) are involved in regulation of key biological processes, and the possible role of their genetic variability has been unexplored so far. Combining genome wide association studies and functional data, we investigated the genetic variability in all lncRNAs. We analyzed 9893 PDAC cases and 9969 controls and identified a genome-wide significant association between the rs7046076 SNP and risk of developing PDAC (P = 9.73 × 10-9 ). This SNP is located in the NONHSAG053086.2 (lnc-SMC2-1) gene and the risk allele is predicted to disrupt the binding of the lncRNA with the micro-RNA (miRNA) hsa-mir-1256 that regulates several genes involved in cell cycle, such as CDKN2B. The CDKN2B region is pleiotropic and its genetic variants have been associated with several human diseases, possibly though an imperfect interaction between lncRNA and miRNA. We present a novel PDAC risk locus, supported by a genome-wide statistical significance and a plausible biological mechanism.

Drug-Drug Interactions between Direct Oral Anticoagulants and Hepatitis C Direct-Acting Antiviral Agents: Looking for Evidence Through a Systematic Review.

BACKGROUND: Direct oral anticoagulants (DOACs), as substrates of cytochrome P450 (CYP) 3A4 and/or P-glycoprotein, are susceptible to drug-drug interactions (DDIs). Hepatitis C direct-acting antiviral agents (DAAs), via P-glycoprotein or CYP3A4 inhibition, may increase DOAC exposure with relevant bleeding risk. We performed a systematic review on DDIs between DOACs and DAAs. METHODS: Two reviewers independently identified studies through electronic databases, until 7 July 2020, supplementing the search by reviewing conference abstracts and the ClinicalTrials.gov website. RESULTS: Of 1386 identified references, four articles were finally included after applying the exclusion criteria. Three phase I clinical studies in healthy volunteers assessed interactions between dabigatran and glecaprevir/pibrentasvir, odalasvir/simeprevir, or sofosbuvir/velpatasvir/voxilaprevir, showing an increase in the dabigatran area under the concentration-time curve (AUC) by 138%, 103%, and 161%, respectively. CONCLUSIONS: DOACs and DAAs are under-investigated for DDI risk. Real-world studies are needed to assess the clinical relevance of the pharmacokinetic interactions with dabigatran and describe the actual spectrum of possible DDIs between DAAs and other DOACs.

Optimal Management of Cirrhotic Ascites: A Review for Internal Medicine Physicians.

Clinical history of liver cirrhosis is characterised by two phases: the asymptomatic phase, also termed 'compensated cirrhosis', and the phase of complications due to the development of portal hypertension and liver dysfunction, also termed 'decompensated cirrhosis', in which patients may develop ascites, the most frequent and clinically relevant complication of liver cirrhosis. Ascites can be classified into uncomplicated and complicated according to the development of refractoriness, spontaneous bacterial peritonitis (SBP) or the association with hepatorenal syndrome (HRS). In this narrative review, we will extensively discuss the optimal pharmacological and non-pharmacological management of cirrhotic ascites with the aim to offer an updated practical guide to Internal Medicine physicians. According to the amount of fluid in the abdominal cavity, uncomplicated ascites is graded from 1 to 3, and the cornerstone of its management consists of restriction of salt intake, diuretics and large-volume paracentesis (LVP); in recent years, long-term administration of human albumin has acquired a new interesting role. Refractory ascites is primarily managed with LVP and transjugular intrahepatic portosystemic shunt (TIPS) placement in selected patients. The occurrence of renal impairment, especially HRS, worsens the prognosis of patients with cirrhotic ascites and deserves a specific treatment. Also, the management of SBP faces the rising and alarming spread of antibiotic resistance. Hepatic hydrothorax may even complicate the course of the disease and its management is a challenge. Last but not least, liver transplantation (LT) is the ultimate and more effective measure to offer to patients with cirrhotic ascites, particularly when complications occur.

The uncertain climate footprint of wetlands under human pressure.

Significant climate risks are associated with a positive carbon-temperature feedback in northern latitude carbon-rich ecosystems, making an accurate analysis of human impacts on the net greenhouse gas balance of wetlands a priority. Here, we provide a coherent assessment of the climate footprint of a network of wetland sites based on simultaneous and quasi-continuous ecosystem observations of CO2 and CH4 fluxes. Experimental areas are located both in natural and in managed wetlands and cover a wide range of climatic regions, ecosystem types, and management practices. Based on direct observations we predict that sustained CH4 emissions in natural ecosystems are in the long term (i.e., several centuries) typically offset by CO2 uptake, although with large spatiotemporal variability. Using a space-for-time analogy across ecological and climatic gradients, we represent the chronosequence from natural to managed conditions to quantify the "cost" of CH4 emissions for the benefit of net carbon sequestration. With a sustained pulse-response radiative forcing model, we found a significant increase in atmospheric forcing due to land management, in particular for wetland converted to cropland. Our results quantify the role of human activities on the climate footprint of northern wetlands and call for development of active mitigation strategies for managed wetlands and new guidelines of the Intergovernmental Panel on Climate Change (IPCC) accounting for both sustained CH4 emissions and cumulative CO2 exchange.

Pegylated interferon-alpha2b plus ribavirin: an efficacious and well-tolerated treatment regimen for patients with hepatitis C virus related histologically proven cirrhosis.

BACKGROUND: Little is known about the efficacy, safety and tolerability of pegylated interferon plus ribavirin treatment in patients with chronic hepatitis Cvirus (HCV) infection and histologically proven fully established cirrhosis. We aimed here to evaluate the safety of this regimen in such patients and to identify baseline and on-treatment predictors of a sustained virological response (SVR). METHODS: Patients with histologically proven, HCV-induced cirrhosis were randomized to receive pegylated interferon-alpha2b (PEG-IFN-alpha2b; 1.0 microg/kg/week, n=56; group A) or recombinant interferon-alpha2b (IFN-alpha2b; 3 million IU three times/week, n=36; group B), each in combination with a weight-based dose of ribavirin (800-1,200 mg/day) for up to 48 weeks. The primary endpoint of the study was the assessment of SVR, defined as undetectable HCV RNA 24 weeks after treatment cessation. RESULTS: Overall, 40% (37/93) of patients attained SVR: 44% (25/57) in group A and 33% (12/36) in group B (P=0.31). SVR rates were significantly higher in genotype 2/3 patients than in genotype 1 patients (69% versus 25%; P<0.0001). Platelet count at baseline, rapid virological response, and early virological response were predictors of SVR. Twelve patients discontinued treatment because of an adverse event and 20 patients required ribavirin dose reduction for the management of anaemia. CONCLUSIONS: PEG-IFN-alpha2b plus ribavirin for 48 weeks is an efficacious and well-tolerated treatment regimen for patients with HCV-induced cirrhosis. Although SVR rates were more satisfactory in genotype 2/3 than in genotype 1 patients, our study identified additional predictors of response that could allow physicians to better manage treatment in this 'difficult-to-cure' subset of patients.