Preoperative nutritional support in patients undergoing pancreatic surgery affects PREPARE score accuracy.

Background: This study aimed to validate the accuracy of the Preoperative Pancreatic Resection (PREPARE) risk score in pancreatic resection patients. Patients and methods: This prospective study included 216 patients who underwent pancreatic resection between January 2015 and December 2018. All patients in our cohort with weight loss or lack of appetite received dietary advice and preoperative oral nutritional supplementation (600 kcal/day). Demographic, clinicopathological, operative, and postoperative data were collected prospectively. The PREPARE score and the predicted risk of major complications were computed for each patient. Differences in major postoperative complications were analyzed using a multivariate Cox proportional hazards regression model. The predicted and observed risks of major complications were tested using the C-statistic. Results: The study included 216 patients [117 men (54.2%)] with a median age of 65.0 (30.0-83.0) years. The majority of patients were classified as American Society of Anesthesiologists (ASA)' Physical Status score II (N = 164/216; 75.9%) and as "low risk" PREPARE score (N = 185/216; 85.6%) before the surgery. Only 4 (1.9%) patients were malnourished, with albumin levels of less than 3.5 g/dl. The most common type of pancreatic resection was a pylorus-preserving pancreaticoduodenectomy (N = 122/216; 56.5%). Major morbidity and 30-day mortality rates were 11.1% and 1.9%, respectively. The type of surgical procedure (hazard ratio [HR]: 3.849; 95% confidence interval [CI]: 1.208-12.264) and ASA score (HR: 3.089; 95% CI: 1.067-8.947) were significantly associated with the incidence of major postoperative complications in multivariate analysis. The receiver operating characteristic curve was 0.657 for incremental values and 0.559 for risk categories, indicating a weak predictive model. Conclusion: The results of the present study suggest that the PREPARE risk score has low accuracy in predicting the risk of major complications in patients with consistent preoperative nutritional support. This limits the use of PREPARE risk score in future preoperative clinical routines.

A scan of all coding region variants of the human genome, identifies 13q12.2-rs9579139 and 15q24.1-rs2277598 as novel risk loci for pancreatic ductal adenocarcinoma.

Coding sequence variants comprise a small fraction of the germline genetic variability of the human genome. However, they often cause deleterious change in protein function and are therefore associated with pathogenic phenotypes. To identify novel pancreatic ductal adenocarcinoma (PDAC) risk loci, we carried out a complete scan of all common missense and synonymous SNPs and analysed them in a case-control study comprising four different populations, for a total of 14 538 PDAC cases and 190 657 controls. We observed a statistically significant association between 13q12.2-rs9581957-T and PDAC risk (P = 2.46 × 10-9), that is in linkage disequilibrium (LD) with a deleterious missense variant (rs9579139) of the URAD gene. Recent findings suggest that this gene is active in peroxisomes. Considering that peroxisomes have a key role as molecular scavengers, especially in eliminating reactive oxygen species, a malfunctioning URAD protein might expose the cell to a higher load of potentially DNA damaging molecules and therefore increase PDAC risk. The association was observed in individuals of European and Asian ethnicity. We also observed the association of the missense variant 15q24.1-rs2277598-T, that belongs to BBS4 gene, with increased PDAC risk (P = 1.53 × 10-6). rs2277598 is associated with body mass index and is in LD with diabetes susceptibility loci. In conclusion, we identified two missense variants associated with the risk of developing PDAC independently from the ethnicity highlighting the importance of conducting reanalysis of genome-wide association studies (GWASs) in light of functional data.

Morphine Analgesia, Cannabinoid Receptor 2, and Opioid Growth Factor Receptor Cancer Tissue Expression Improve Survival after Pancreatic Cancer Surgery.

Pancreatic cancer (PDAC) has a poor prognosis despite surgical removal and adjuvant therapy. Additionally, the effects of postoperative analgesia with morphine and piritramide on survival among PDAC patients are unknown, as are their interactions with opioid/cannabinoid receptor gene expressions in PDAC tissue. Cancer-specific survival data for 71 PDAC patients who underwent radical surgery followed by postoperative analgesia with morphine (n = 48) or piritramide (n = 23) were therefore analyzed in conjunction with opioid/cannabinoid receptor gene expressions in the patients' tumors. Receptor gene expressions were determined using the quantitative real-time polymerase chain reaction. Patients receiving morphine had significantly longer cancer-specific survival (CSS) than those receiving piritramide postoperative analgesia (median 22.4 vs. 15 months; p = 0.038). This finding was supported by multivariate modelling (p < 0.001). The morphine and piritramide groups had similar morphine equipotent doses, receptor expression, and baseline characteristics. The opioid/cannabinoid receptor gene expression was analyzed in a group of 130 pancreatic cancer patients. Of the studied receptors, high cannabinoid receptor 2 (CB2) and opioid growth factor receptor (OGFR) gene expressions have a positive influence on the length of overall survival (OS; p = 0.029, resp. p = 0.01). Conversely, high delta opioid receptor gene expression shortened OS (p = 0.043). Multivariate modelling indicated that high CB2 and OGFR expression improved OS (HR = 0.538, p = 0.011, resp. HR = 0.435, p = 0.001), while high OPRD receptor expression shortened OS (HR = 2.264, p = 0.002). Morphine analgesia, CB2, and OGFR cancer tissue gene expression thus improved CSS resp. OS after radical PDAC surgery, whereas delta opioid receptor expression shortened OS.

Exploring the Neandertal legacy of pancreatic ductal adenocarcinoma risk in Eurasians.

BACKGROUND: The genomes of present-day non-Africans are composed of 1-3% of Neandertal-derived DNA as a consequence of admixture events between Neandertals and anatomically modern humans about 50-60 thousand years ago. Neandertal-introgressed single nucleotide polymorphisms (aSNPs) have been associated with modern human disease-related traits, which are risk factors for pancreatic ductal adenocarcinoma (PDAC), such as obesity, type 2 diabetes, and inflammation. In this study, we aimed at investigating the role of aSNPs in PDAC in three Eurasian populations. RESULTS: The high-coverage Vindija Neandertal genome was used to select aSNPs in non-African populations from 1000 Genomes project phase 3 data. Then, the association between aSNPs and PDAC risk was tested independently in Europeans and East Asians, using existing GWAS data on more than 200 000 individuals. We did not find any significant associations between aSNPs and PDAC in samples of European descent, whereas, in East Asians, we observed that the Chr10p12.1-rs117585753-T allele (MAF = 10%) increased the risk to develop PDAC (OR = 1.35, 95%CI 1.19-1.54, P = 3.59 × 10-6), with a P-value close to a threshold that takes into account multiple testing. CONCLUSIONS: Our results show only a minimal contribution of Neandertal SNPs to PDAC risk.

The PANcreatic Disease ReseArch (PANDoRA) consortium: Ten years' experience of association studies to understand the genetic architecture of pancreatic cancer.

Pancreatic cancer has an incidence that almost matches its mortality. Only a small number of risk factors and 33 susceptibility loci have been identified. so Moreover, the relative rarity of pancreatic cancer poses significant hurdles for research aimed at increasing our knowledge of the genetic mechanisms contributing to the disease. Additionally, the inability to adequately power research questions prevents small monocentric studies from being successful. Several consortia have been established to pursue a better understanding of the genetic architecture of pancreatic cancers. The Pancreatic disease research (PANDoRA) consortium is the largest in Europe. PANDoRA is spread across 12 European countries, Brazil and Japan, bringing together 29 basic and clinical research groups. In the last ten years, PANDoRA has contributed to the discovery of 25 susceptibility loci, a feat that will be instrumental in stratifying the population by risk and optimizing preventive strategies.

Painless form of chronic pancreatitis - multicentre study.

BACKGROUND: The painless form of chronic pancreatitis is one of the rarer forms of the disease. While 80% to 90% of all chronic pancreatitis cases have abdominal pain as their clinical symptom, a smaller proportion of persons with chronic pancreatitis do not report typical pain. This form of the disease is often associated with exocrine and endocrine pancreatic insufficiency and weight loss, but the absence of pain symptoms may initially lead to misdiagnosis. METHODS: In a cohort of 257 people with chronic pancreatitis, the painless form was diagnosed in 30 individuals (11.6%), with an average age of 56 years and a predominance of men (71.4%). Thirty-eight percent were non-smokers and 47.6% of patients smoked up to 10 cigarettes per day. Alcohol intake of less than 40 g per day was reported by 61.9% of subjects. A quarter were moderately overweight, with a mean BMI of 26.5. Newly diagnosed diabetes mellitus had 25.7% of the subjects. RESULTS: A frequent finding was the demonstration of morphological changes, with calcifications found in 85,7% and dilatation of the pancreatic duct greater than 6.0 mm in 66%. A surprising finding was the presence of metabolic syndrome in 42.8% and the most frequent finding was the demonstration of decreased external pancreatic secretion (90%). CONCLUSION: Painless chronic pancreatitis is usually treated conservatively. We demonstrate a subset of 28 patients with painless chronic pancreatitis treated surgically. Most frequent indications were benign stenosis of the intrapancreatic bile duct and stenosis of the pancreatic duct. Although approximately 1 in 10 people with chronic pancreatitis present with a painless form of it, so that the form of the disease is described as rare, this does not change the fact that management of these people is still not optimal.

Major iatrogenic bile duct injury during elective cholecystectomy: a Czech population register-based study.

PURPOSE: Bile duct injury (BDI) remains the most serious complication following cholecystectomy. However, the actual incidence of BDI in the Czech Republic remains unknown. Hence, we aimed to identify the incidence of major BDI requiring operative reconstruction after elective cholecystectomy in our region despite the prevailing modern 4 K Ultra HD laparoscopy and Critical View of Safety (CVS) standards implemented in daily surgical practice among the Czech population. METHODS: In the absence of a specific registry for BDI, we analysed data from The Czech National Patient Register of Reimbursed Healthcare Services, where all procedures are mandatorily recorded. We investigated 76,345 patients who were enrolled for at least a year and underwent elective cholecystectomy during the period from 2018-2021. In this cohort, we examined the incidence of major BDI following the reconstruction of the biliary tract and other complications. RESULTS: A total of 76,345 elective cholecystectomies were performed during the study period, and 186 major BDIs were registered (0.24%). Most elective cholecystectomies were performed laparoscopically (84.7%), with the remaining open (15.3%). The incidence of BDI was higher in the open surgery group (150 BDI/11700 cases/1.28%) than in laparoscopic cholecystectomy (36 BDI/64645 cases/0.06%). Furthermore, the total hospital stays with BDI after reconstruction was 13.6 days. However, the majority of laparoscopic elective cholecystectomies (57,914, 89.6%) were safe and standard procedures with no complications. CONCLUSION: Our study corroborates the findings of previous nationwide studies. Therefore, though laparoscopic cholecystectomy is reliable, the risks of BDI cannot be eliminated.

Fluorescence In Situ Hybridization in Primary Diagnosis of Biliary Strictures: A Single-Center Prospective Interventional Study.

Background and aims: Diagnosis of the biliary stricture remains a challenge. In view of the low sensitivity of brush cytology (BC), fluorescence in situ hybridization (FISH) has been reported as a useful adjunctive test in patients with biliary strictures. We aimed to determine performance characteristics of BC and FISH individually and in combination (BC + FISH) in the primary diagnosis of biliary strictures. Methods: This single-center prospective study was conducted between April 2019 and January 2021. Consecutive patients with unsampled biliary strictures undergoing first endoscopic retrograde cholangiopancreatography in our institution were included. Tissue specimens from two standardized transpapillary brushings from the strictures were examined by routine cytology and FISH. Histopathological confirmation after surgery or 12-month follow-up was regarded as the reference standard for final diagnosis. Results: Of 109 enrolled patients, six were excluded and one lost from the final analysis. In the remaining 102 patients (60.8% males, mean age 67.4, range 25-92 years), the proportions of benign and malignant strictures were 28 (27.5%) and 74 (72.5%), respectively. The proportions of proximal and distal strictures were 26 (25.5%) and 76 (74.5%), respectively. In comparison to BC alone, FISH increased the sensitivity from 36.1% to 50.7% (p = 0.076) while maintaining similar specificity (p = 0.311). Conclusions: Dual-modality tissue evaluation using BC + FISH showed an improving trend in sensitivity for the primary diagnosis of biliary strictures when compared with BC alone.

Genetic and non-genetic risk factors for early-onset pancreatic cancer.

BACKGROUND: Early-onset pancreatic cancer (EOPC) represents 5-10% of all pancreatic ductal adenocarcinoma (PDAC) cases, and the etiology of this form is poorly understood. It is not clear if established PDAC risk factors have the same relevance for younger patients. This study aims to identify genetic and non-genetic risk factors specific to EOPC. METHODS: A genome-wide association study was performed, analysing 912 EOPC cases and 10 222 controls, divided into discovery and replication phases. Furthermore, the associations between a polygenic risk score (PRS), smoking, alcohol consumption, type 2 diabetes and PDAC risk were also assessed. RESULTS: Six novel SNPs were associated with EOPC risk in the discovery phase, but not in the replication phase. The PRS, smoking, and diabetes affected EOPC risk. The OR comparing current smokers to never-smokers was 2.92 (95% CI 1.69-5.04, P = 1.44 × 10-4). For diabetes, the corresponding OR was 14.95 (95% CI 3.41-65.50, P = 3.58 × 10-4). CONCLUSION: In conclusion, we did not identify novel genetic variants associated specifically with EOPC, and we found that established PDAC risk variants do not have a strong age-dependent effect. Furthermore, we add to the evidence pointing to the role of smoking and diabetes in EOPC.

EUS-guided transluminal drainage using lumen-apposing metal stents with or without coaxial plastic stents for treatment of walled-off necrotizing pancreatitis: a prospective bicentric randomized controlled trial.

BACKGROUND AND AIMS: Lumen-apposing metal stents (LAMSs) have proven to be effective for drainage of pancreatic walled-off necrosis (WON), although associated adverse events (AEs) have been reported. Anchoring coaxial double-pigtail plastic stents (DPSs) within LAMSs have been proposed to prevent LAMS-related AEs but have not been assessed in prospective studies. We aimed to evaluate the utility of such measures with a randomized controlled trial. METHODS: We randomly assigned consecutive patients with WON indications for drainage to EUS-guided transluminal drainage using LAMSs with (group A) or without (group B) DPSs. All LAMSs were to be removed after 3 weeks had elapsed from the index procedure with a preceding CT to decide whether additional steps needed to be taken (eg, transluminal necrosectomy or placing transluminal plastic stents in patients with incomplete resolution of WON). The main outcomes were failure of the index method, defined as necessity of reintervention (endoscopic, percutaneous, or surgical) before LAMS removal because of LAMS-related AEs and/or clinical deterioration; AE rates; and mortality with the LAMS in place. Variables were evaluated using the Mann-Whitney U test, χ2 test, or Fisher exact test as appropriate. P < .05 was considered significant. RESULTS: Sixty-seven patients (37.3% women; mean age, 54 ± 14.4 years) underwent LAMS placement with (n = 34) or without (n = 33) DPS placement in 2 tertiary centers. Baseline characteristics including demographics, etiology, comorbidity, and clinical presentation (sterile vs infected necrosis) were comparable between both groups. The technical success rate in placing LAMSs and DPSs was 100%. The global rate of AEs was significantly lower in group A versus group B (20.7% vs 51.5%, respectively; P = .008). Stent occlusion was the most frequently observed AE (14.7% vs 36.3%, P = .042). Failure of the index method was lower in group A versus group B (29.4% vs 48.5%, respectively; P = .109); however, the difference did not achieve statistical significance. The same applied to the mortality rate with LAMSs in place (2.9% vs 12.1%, P = .197). CONCLUSIONS: The addition of a coaxial DPS within a LAMS was associated with a significantly lower global rate of AEs and stent occlusion rate in EUS-guided drainage of WON. (Clinical trial registration number: NCT03923686.).

Association between a polymorphic variant in the CDKN2B-AS1/ANRIL gene and pancreatic cancer risk.

Genes carrying high-penetrance germline mutations may also be associated with cancer susceptibility through common low-penetrance genetic variants. To increase the knowledge on genetic pancreatic ductal adenocarcinoma (PDAC) aetiology, the common genetic variability of PDAC familial genes was analysed in our study. We conducted a multiphase study analysing 7745 single nucleotide polymorphisms (SNPs) from 29 genes reported to harbour a high-penetrance PDAC-associated mutation in at least one published study. To assess the effect of the SNPs on PDAC risk, a total of 14 666 PDAC cases and 221 897 controls across five different studies were analysed. The T allele of the rs1412832 polymorphism, that is situated in the CDKN2B-AS1/ANRIL, showed a genome-wide significant association with increased risk of developing PDAC (OR = 1.11, 95% CI = 1.07-1.15, P = 5.25 × 10-9 ). CDKN2B-AS1/ANRIL is a long noncoding RNA, situated in 9p21.3, and regulates many target genes, among which CDKN2A (p16) that frequently shows deleterious somatic and germline mutations and deregulation in PDAC. Our results strongly support the role of the genetic variability of the 9p21.3 region in PDAC aetiopathogenesis and highlight the importance of secondary analysis as a tool for discovering new risk loci in complex human diseases.

Silver-Based Dressings in the Prevention of the Incisional Surgical Site Infection: A Prospective Multicenter Observational Controlled Trial.

Background: A new silver-based dressing has been designed to reduce surgical sited infections. Patients and Methods: A prospective multicenter observational study was conducted from January 2020 to October 2021. Patients with and without silver-based dressing after surgical incision were observed and their data analyzed. The study aimed to assess the incidence of incisional surgical site infection and primary healing after general surgery procedures. Results: Overall, 218 patients with silver-based (n = 109) and conventional silver-free dressing (n = 109) were analyzed. Surgical site infection (SSI) and primary incision healing were reported in 10 (9.2%) versus 21 (19.3%) (p = 0.037) and in 95 (87.2%) versus 86 (78.9%) (p = 0.107) patients treated with and without silver-based dressing, respectively. Conclusions: Silver-based dressing demonstrated a lower incidence of incisional SSI and improved primary healing in comparison with patients in whom conventional non-silver-based dressing has been used.

Isolated Gastric Metastases of Pancreatic Ductal Adenocarcinoma following Radical Resection-Impact of Endosonography-Guided Fine Needle Aspiration Tract Seeding.

BACKGROUND: Endosonography-guided fine needle aspiration biopsy (EUS-FNA)-associated metachronous gastric seeding metastases (GSM) of pancreatic ductal adenocarcinoma (PDAC) represent a serious condition with insufficient evidence. METHODS: Retrospective analysis of PDAC resections with a curative-intent, proven pathological diagnosis of PDAC, preoperative EUS-FNA and post-resection follow-up of at least 60 months. The systematic literature search of published data was used for the GSM growth evaluation using Pearson correlation and the linear regression analyses. RESULTS: The inclusion criteria met 59/134 cases, 16 (27%) had retained needle tract (15 following distal pancreatectomy, 1 following pylorus-sparing head resection). In total, 3/16 cases (19%) developed identical solitary GSM (10-26th month following primary surgery) and were radically resected. A total of 30 published cases of PDAC GSM following EUS-FNA were identified. Lesion was resected in 20 distal pancreatectomy cases with complete information in 14 cases. A correlation between the metastasis size and time (r = 0.612) was proven. The regression coefficient b = 0.72 expresses the growth of 0.72 mm per month. CONCLUSIONS: The GSM represent a preventable and curable condition. A remarkably high number of GSM following EUS-FNA was identified, leading to follow-up recommendation of EUS-FNA sampled patients. Multimodal management (gastric resection, adjuvant chemotherapy) may prolong survival.

The short- and long-term outcomes of pancreaticoduodenectomy for distal cholangiocarcinoma.

BACKGROUND: The aim of the study was to calculate the short-term and long-term outcomes of curative-intent surgery in distal cholangiocarcinoma (DCC) patients to identify potential prognostic factors. PATIENTS AND METHODS: A retrospective cohort study of 32 consecutive DCC patients treated with pancreaticoduodenectomy between 2009-2017. The clinicopathological and histopathological data were evaluated for prognostic factors using the univariable Cox regression analysis. The Overall Survival (OS) was estimated using the Kaplan-Meier analysis. RESULTS: The study comprised a total of 32 patients, with a mean age of 65.8 (± 9.0) years at the time of surgery. R0 resection was achieved in 25 (86.2%) patients, 19 (65.5%) patients received adjuvant oncological therapy. The OS rates at 1, 3 and 5 years were 62.5%, 37.5% and 21.9%, respectively. The 90-day mortality was 3/32 (9.4%) accounting for one-fourth of the first-year mortality rate. The median OS was 28.5 months. The only statistically significant prognostic factor was vascular resection, which was associated with worse OS in the univariable analysis (HR: 3.644; 95%-CI: 1.179-11.216, P=0.025). An age less than 65 years, ASA grade I/II, hospital stay of fewer than 15 days, R0 resection, lymph node ratio less than 0.2 and adjuvant oncological therapy tended to be associated with better OS but without statistically significant relevance. CONCLUSION: The main factor directly influencing the survival of DCC patients is surgical complications. Surgical mortality comprises a significant group of patients, who die in the first year following pancreaticoduodenectomy. Vascular resection is the most important negative prognostic factor for long-term survival.

Surgical treatment of duodenal adenocarcinoma: ampullary vs. non-ampullary, short- and long-term outcomes.

BACKGROUND: The aim of this study was to evaluate symptoms, diagnostic methods, short- and long-term outcomes of surgical treatment in patients with duodenal adenocarcinoma. PATIENTS AND METHODS: A single center, retrospective, observational study of 52 consecutive patients with duodenal adenocarcinoma operated on with curative intent between 2006 - 2019. Duodenectomy as part of a hemipancreatoduodenectomy or total pancreatectomy procedure was performed for ADAC (ampullary duodenal/intestinal adenocarcinoma) or NADAC (non-ampullary duodenal adenocarcinoma). RESULTS: Prevailing symptoms were obstructive jaundice in the ADAC group (P<0.0001) and bleeding in the NADAC group (P=0.005), with larger tumor size in patients with NADAC (P=0.001). Complication rate, morbidity and mortality were comparable. Primary total pancreatoduodenectomy predominated in the NADAC group, 16.6% vs. 2.9%, and salvage completion pancreatectomy in the ADAC group, 6% vs. 0%. Significant prognostic factors for OS were perineural invasion (P=0.006) and adjuvant chemotherapy (P=0.045) in the ADAC group, and for DFS the total number of resected lymph nodes (P=0.042) and lymph node ratio (P=0.031) in the NADAC group. Median OS is 21 months and 5-year survival 27.3% in the NADAC group and 41.5 months and 52% in the ADAC group. CONCLUSION: Ampullary duodenal/intestinal adenocarcinomas are smaller than non-ampullary at diagnosis, with a higher rate of lymph node metastases, but with a better prognosis and long-term outcome in the presented cohort. Oral localisation of NADAC prevailed in the present cohort. Perineural invasion and postoperative oncological therapy are significant prognostic factors for OS in ADAC, but the total number of lymph nodes and lymph node ratio are significant prognostic factors for DFS in NADAC.

Identification of Recessively Inherited Genetic Variants Potentially Linked to Pancreatic Cancer Risk.

Although 21 pancreatic cancer susceptibility loci have been identified in individuals of European ancestry through genome-wide association studies (GWASs), much of the heritability of pancreatic cancer risk remains unidentified. A recessive genetic model could be a powerful tool for identifying additional risk variants. To discover recessively inherited pancreatic cancer risk loci, we performed a re-analysis of the largest pancreatic cancer GWAS, the Pancreatic Cancer Cohort Consortium (PanScan) and the Pancreatic Cancer Case-Control Consortium (PanC4), including 8,769 cases and 7,055 controls of European ancestry. Six single nucleotide polymorphisms (SNPs) showed associations with pancreatic cancer risk according to a recessive model of inheritance. We replicated these variants in 3,212 cases and 3,470 controls collected from the PANcreatic Disease ReseArch (PANDoRA) consortium. The results of the meta-analyses confirmed that rs4626538 (7q32.2), rs7008921 (8p23.2) and rs147904962 (17q21.31) showed specific recessive effects (p<10-5) compared with the additive effects (p>10-3), although none of the six SNPs reached the conventional threshold for genome-wide significance (p < 5×10-8). Additional bioinformatic analysis explored the functional annotations of the SNPs and indicated a possible relationship between rs36018702 and expression of the BCL2L11 and BUB1 genes, which are known to be involved in pancreatic biology. Our findings, while not conclusive, indicate the importance of considering non-additive genetic models when performing GWAS analysis. The SNPs associated with pancreatic cancer in this study could be used for further meta-analysis for recessive association of SNPs and pancreatic cancer risk and might be a useful addiction to improve the performance of polygenic risk scores.

Genetic Polymorphisms Involved in Mitochondrial Metabolism and Pancreatic Cancer Risk.

BACKGROUND: The mitochondrial metabolism has been associated with pancreatic ductal adenocarcinoma (PDAC) risk. Recent evidence also suggests the involvement of the genetic variability of the mitochondrial function in several traits involved in PDAC etiology. However, a systematic investigation of the genetic variability of mitochondrial genome (mtSNP) and of all the nuclear genes involved in its functioning (n-mtSNPs) has never been reported. METHODS: We conducted a two-phase association study of mtSNPs and n-mtSNPs to assess their effect on PDAC risk. We analyzed 35,297 n-mtSNPs and 101 mtSNPs in up to 55,870 individuals (12,884 PDAC cases and 42,986 controls). In addition, we also conducted a gene-based analysis on 1,588 genes involved in mitochondrial metabolism using Multi-marker Analysis of GenoMic Annotation (MAGMA) software. RESULTS: In the discovery phase, we identified 49 n-mtSNPs and no mtSNPs associated with PDAC risk (P < 0.05). In the second phase, none of the findings were replicated. In the gene-level analysis, we observed that three genes (TERT, SUGCT, and SURF1) involved in the mitochondrial metabolism showed an association below the Bonferroni-corrected threshold of statistical significance (P = 0.05/1588 = 3.1 × 10-5). CONCLUSIONS: Even though the mitochondrial metabolism might be involved in PDAC etiology, our results, obtained in a study with one of the largest sample sizes to date, show that neither n-mtSNPs nor mtSNPs are associated with PDAC risk. IMPACT: This large case-control study does not support a role of the genetic variability of the mitochondrial function in PDAC risk.

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.

Associations between pancreatic expression quantitative traits and risk of pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal cancers. Its poor prognosis is predominantly due to the fact that most patients remain asymptomatic until the disease reaches an advanced stage, alongside the lack of early markers and screening strategies. A better understanding of PDAC risk factors is essential for the identification of groups at high risk in the population. Genome-wide association studies (GWAS) have been a powerful tool for detecting genetic variants associated with complex traits, including pancreatic cancer. By exploiting functional and GWAS data, we investigated the associations between polymorphisms affecting gene function in the pancreas (expression quantitative trait loci, eQTLs) and PDAC risk. In a two-phase approach, we analysed 13 713 PDAC cases and 43 784 controls and identified a genome-wide significant association between the A allele of the rs2035875 polymorphism and increased PDAC risk (P = 7.14 × 10-10). This allele is known to be associated with increased expression in the pancreas of the keratin genes KRT8 and KRT18, whose increased levels have been reported to correlate with various tumour cell characteristics. Additionally, the A allele of the rs789744 variant was associated with decreased risk of developing PDAC (P = 3.56 × 10-6). This single nucleotide polymorphism is situated in the SRGAP1 gene and the A allele is associated with higher expression of the gene, which in turn inactivates the cyclin-dependent protein 42 (CDC42) gene expression, thus decreasing the risk of PDAC. In conclusion, we present here a functional-based novel PDAC risk locus and an additional strong candidate supported by significant associations and plausible biological mechanisms.

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.