Hepatitis B and C Virus Infection and Risk of Pancreatic Cancer: A Population-Based Cohort Study (JPHC Study Cohort II)

Improving the prognosis of pancreatic cancer: insights from epidemiology, genomic alterations, and therapeutic challenges

Pancreatic cancer, notorious for its late diagnosis and aggressive progression, poses a substantial challenge owing to scarce treatment alternatives. This review endeavors to furnish a holistic insight into pancreatic cancer, encompassing its epidemiology, genomic characterization, risk factors, diagnosis, therapeutic strategies, and treatment resistance mechanisms. We delve into identifying risk factors, including genetic predisposition and environmental exposures, and explore recent research advancements in precursor lesions and molecular subtypes of pancreatic cancer. Additionally, we highlight the development and application of multi-omics approaches in pancreatic cancer research and discuss the latest combinations of pancreatic cancer biomarkers and their efficacy. We also dissect the primary mechanisms underlying treatment resistance in this malignancy, illustrating the latest therapeutic options and advancements in the field. Conclusively, we accentuate the urgent demand for more extensive research to enhance the prognosis for pancreatic cancer patients.

Association between hepatitis B or hepatitis C virus infection and risk of pancreatic cancer: a systematic review and meta-analysis of cohort studies

Background and aim

With conflicting data from previous observational studies on the relationship between hepatitis B virus (HBV) or hepatitis C virus (HCV) infection and pancreatic cancer (PC), we decided to conduct a systematic review and meta-analysis in order to evaluate any potential association.

Design

This is a systematic review and meta-analysis.

Methods

We conducted a search of three databases (PubMed, Embase, and Web of Science) from the time of their creation up to June 2023. The summary results, including hazard ratio (HR) with 95% confidence interval (CI), were pooled using a generic inverse variance method and a random-effects model. Furthermore, subgroup and sensitivity analyses were conducted.

Results

In this meta-analysis, 22 cohort studies with a total of 10,572,865 participants were analyzed. Meta-analysis from 15 cohort studies revealed that HBV infection was correlated with an increased risk of PC (HR = 1.53, 95% CI: 1.40-1.68, p < 0.00001) with no heterogeneity (I2 = 0%, p = 0.49). Meta-analysis from 14 cohort studies showed that HCV infection was associated with an increased risk of PC (HR = 1.82, 95% CI: 1.51-2.21, p < 0.00001). Most of our subgroup analyses yielded similar results. Meta-analysis from four cohort studies indicated that co-infection with HBV and HCV was linked to an increased risk of PC (HR = 2.32, 95% CI: 1.40-3.85, p = 0.001) with no heterogeneity observed (I2 = 0%, p = 0.60). The results of sensitivity analyses were robust.

Conclusion

Our meta-analysis showed that HBV/HCV infection or co-infection with HBV and HCV was associated with an increased risk of PC. Future prospective cohort studies need to take into account various ethnicities and any confounding factors, as well as investigate the potential mechanisms of PC development in those with HBV/HCV.

Trial registration

Open Science Framework registries (No: osf.io/n64ua).

Kashmiri refugees at the verge of hepatitis B and C epidemic in the State of Azad Jammu and Kashmir, Pakistan

OBJECTIVE

To determine the seroprevalence of hepatitis B and C among immigrants residing refugee camps in Muzaffarabad, Azad Kashmir, Pakistan, and to identify possible risk factors for hepatitis B virus (HBV) and hepatitis C virus (HCV) transmission.

METHODS

Around 1,225 individuals inhabiting Muzaffarabad refugee camps, participated in the study. A qualitative Immuno-Chromatographic Technique was used for initial screening and PCR test was used for detection of HBV and HCV in participants. The major risk factors for HBV and HCV transmission were assessed using a questionnaire approach.

RESULTS

Around 86 (7.0%) individuals were observed for hepatitis B surface antigen (HBsAg) presence, and 215 (17.5%) individuals were found positive for Anti-HCV. Only 32 (2.6%) individuals were confirmed for HBV DNA and 126 (10.3%) individuals were positive for HCV RNA after PCR. Demographically, both HBsAg and Anti-HCV were found more prevalent in female (4.4% HBsAg and 10.8% Anti-HCV) population as compared to male (2.6% HBsAg and 6.7% Anti-HCV) population. Surprisingly, the HBsAg (23.5%) and Anti-HCV (41.1%) appeared to be more frequent in the age group 62–75 years. Previous history of hepatitis in the family (p < 0.0001), blood transfusion (p = 0.0197) dental treatment (p < 0.0001) and tattooing or piercing on any part of the body (p = 0.0028) were assessed as significant risk factors in HBV and HCV transmission.

CONCLUSIONS

Presence of 7.0% HBsAg and 17.5% Anti-HCV in a small fragment of the migrant population cannot be overlooked. Lack of awareness among people and negligence of health department could escalate the situation.

Low MICA Gene Expression Confers an Increased Risk of Graves' Disease: A Mendelian Randomization Study

Background: Expression of natural killer group 2 member D (NKG2D) ligand (NKG2DL) plays a major role as a "danger signal" on stressed cells to promote removal of the latter by NKG2D-expressing cytotoxic lymphocytes. NKG2DL expression has been found in peripheral immune cells as well, such as in macrophages; however, the effect of this expression is yet to be determined. Methods: We determined instrumental variables (IVs; R² <0.01 in linkage disequilibrium), explaining the major variance in major histocompatibility complex class I chain-related protein A (MICA) and B (MICB) gene expression levels from the expression-quantitative trait locus (eQTL) of NKG2DLs based on the RNA-seq analysis of peripheral blood mononuclear cells (PBMCs) from 381 Japanese. Simultaneously, the target outcomes were filtered by PheWAS from 58 health risks, using a community-based cohort study composed of 44,739 Japanese residents. Finally, we estimated the causal effect of gene expression levels on the outcomes using the Mendelian randomization approach. Results: We determined nine and four IVs, explaining 87.6% and 33.0% of MICA and MICB gene expression levels, respectively. In the association test, we identified 10 or 13 significant outcomes associated with the MICA or MICB eQTLs, respectively, as well as the causal effect of MICA expression on Graves' disease (GD) (p = 4.2 × 10^-3; odds ratio per 1 S.D. difference in the expression: 0.983 [confidence interval: 0.971-0.995]), using the weighted median estimator, without significant pleiotropy (p > 0.05), and the results were consistent across the sensitivity analyses. Conclusions: Our study provide novel evidence associating NKG2DL expression with GD, an autoimmune thyroiditis; direction of the effect indicated the immunoregulatory role of MICA expression in PBMCs, suggesting the importance of further functional assays in inflammatory diseases.

Chronic hepatitis C infection is associated with higher incidence of extrahepatic cancers in a Canadian population based cohort

INTRODUCTION

Chronic infection with hepatitis C virus (HCV) is an established risk factor for liver cancer. Although several epidemiologic studies have evaluated the risk of extrahepatic malignancies among people living with HCV, due to various study limitations, results have been heterogeneous.

METHODS

We used data from the British Columbia Hepatitis Testers Cohort (BC-HTC), which includes all individuals tested for HCV in the Province since 1990. We assessed hepatic and extrahepatic cancer incidence using data from BC Cancer Registry. Standardized incidence ratios (SIR) comparing to the general population of BC were calculated for each cancer site from 1990 to 2016.

RESULTS

In total, 56,823 and 1,207,357 individuals tested positive and negative for HCV, respectively. Median age at cancer diagnosis among people with and without HCV infection was 59 (interquartile range (IQR): 53-65) and 63 years (IQR: 54-74), respectively. As compared to people living without HCV, a greater proportion of people living with HCV-infection were men (66.7% vs. 44.7%, P-value <0.0001), had comorbidities (25.0% vs. 16.3%, P-value <0.0001) and were socially deprived (35.9% vs. 25.0%, P-value <0.0001). The SIRs for liver (SIR 33.09; 95% CI 29.80-36.39), anal (SIR: 2.57; 95% CI 1.52-3.63), oesophagus (SIR: 2.00; 95% CI 1.17-2.82), larynx (SIR: 3.24; 95% CI 1.21-5.27), lung (SIR: 2.20; 95% CI 1.82-2.58), and oral (SIR: 1.78; 95% CI 1.33-2.23) cancers were significantly higher among individuals living with HCV. The SIRs for bile duct and pancreatic cancers were significantly elevated among both individuals living with (SIR; 95% CI: 2.20; 1.27-3.14; 2.18; 1.57-2.79, respectively) and without HCV (SIR; 95% CI: 2.12; 1.88-2.36; 1.20; 1.11-1.28, respectively).

DISCUSSION/CONCLUSION

In this study, HCV infection was associated with increased incidence of several extrahepatic cancers. The elevated incidence of multiple cancers among negative HCV testers highlights the potential contributions of screening bias and increased cancer risks associated with factors driving acquisition of infection among this population compared to the general population. Early HCV diagnosis and treatment as well as public health prevention strategies are needed to reduce the risk of extrahepatic cancers among people living with HCV and potentially populations who are at higher risk of HCV infection.

Cancer in People with and without Hepatitis C Virus Infection: Comparison of Risk Before and After Introduction of Direct-Acting Antivirals

BACKGROUND

Chronic hepatitis C virus (HCV) infection is a leading cause of liver cancer. The association of HCV infection with extrahepatic cancers, and the impact of direct-acting antiviral (DAA) treatment on these cancers, is less well known.

METHODS

We conducted a cohort study in a healthcare delivery system. Using electronic health record data from 2007 to 2017, we determined cancer incidence, overall and by type, in people with HCV infection and by DAA treatment status. All analyses included comparisons with a reference population of people without HCV infection. Covariate-adjusted Poisson models were used to estimate incidence rate ratios.

RESULTS

2,451 people with HCV and 173,548 people without HCV were diagnosed with at least one type of cancer. Compared with people without HCV, those with HCV were at higher risk for liver cancer [adjusted incidence rate ratio (aIRR) = 31.4, 95% confidence interval (CI) = 28.9-34.0], hematologic cancer (aIRR = 1.3, 95% CI = 1.1-1.5), lung cancer (aIRR = 1.3, 95% CI = 1.2-1.5), pancreatic cancer (aIRR = 2.0, 95% CI = 1.6-2.5), oral/oropharynx cancer (aIRR = 1.4, 95% CI = 1.1-1.8), and anal cancer (aIRR = 1.6, 95% CI = 1.1-2.4). Compared with people without HCV, the aIRR for liver cancer was 31.9 (95% CI = 27.9-36.4) among DAA-untreated and 21.2 (95% CI = 16.8-26.6) among DAA-treated, and the aIRR for hematologic cancer was 1.5 (95% CI = 1.1-2.0) among DAA-untreated and 0.6 (95% CI = 0.3-1.2) among DAA-treated.

CONCLUSIONS

People with HCV infection were at increased risk of liver cancer, hematologic cancer, and some other extrahepatic cancers. DAA treatment was associated with reduced risk of liver cancers and hematologic cancers.

IMPACT

DAA treatment is important for reducing cancer incidence among people with HCV infection.

Prognostic impact of hepatitis B virus infection in patients with primary cervical cancer

Background

Hepatitis B virus (HBV) infection has been associated with an increased risk of a few malignancies. However, the prognostic impact of HBV infection remains unclear in cervical cancer.

Objective

To explore the association between HBV infection and survival outcomes of patients with primary cervical cancer, using overall survival (OS) and disease‐free survival (DFS) as primary endpoints.

Methods

This analysis was performed retrospectively with newly diagnosed cervical cancer patients admitted to the Department of Gynecologic Oncology at the Sun Yat‐sen Memorial Hospital of Sun Yat‐sen University from June 2013 to October 2019, who were enrolled and followed up. The Kaplan–Meier method and Cox proportional hazard analysis were used to examine the performance of HBV infection in predicting OS and DFS.

Results

Patients were followed up for a median of 37.17 months (95% CI, 34.69–39.65). Among the 695 patients, 87 (12.5%) were serologically positive for hepatitis B surface antigen (HBsAg), and 276 (39.7%) had a prior history of HBV infection. There was no significant difference between HBsAg‐positive group and HBsAg‐negative patients concerning OS or DFS. Multivariate analysis showed prior HBV infection was an independent favorable prognosticator for OS (HR, 0.335; 95% CI, 0.153–0.0.734; p = 0.006) and DFS (HR, 0.398; 95% CI, 0.208–0.691; p = 0.002).

Conclusion

We provide the first clinical evidence that suggests prior HBV infection as an independent favorable prognostic factor for patients with primary cervical cancer.

Associations between hepatitis B virus exposure and the risk of extrahepatic digestive system cancers: A hospital-based, case-control study (SIGES)

OBJECTIVES

This case-control study was aimed to investigate associations between HBV infection and extrahepatic digestive system cancers.

METHODS

The patients of gastric, small intestinal, colonic, rectal, anal, biliary tract, and pancreatic cancers were retrospectively collected between 2016.5 and 2017.12. Simultaneously, the healthy controls were collected from the health check-up registry, and cancer-free status was confirmed based on medical records. Propensity score matching was performed to reduce bias. Multinomial logit model and conditional logistic regression model were used to assess the risk of individual cancer according to HBV serological markers and classifications.

RESULTS

Totally, 4748 patients involving seven cancers, and 57,499 controls were included. After matching, HBsAg was associated with increased risk of gastric cancer (aOR = 1.39, 95% CI: 1.05-1.85), and anti-HBs served as a protective factor for gastric (aOR = 0.72, 95% CI: 0.61-0.85), colonic (aOR = 0.73, 95% CI: 0.60-0.89), rectal (aOR = 0.73, 95% CI: 0.63-0.85), and pancreatic (aOR = 0.58, 95% CI: 0.42-0.82) cancers. Compared to subgroups with non-infection and vaccination status, inactive HBsAg carriers and active HBV infection subgroup were correlated with gastric carcinogenesis (aOR = 1.41, 95% CI: 1.03-1.93). However, no clear association was found between HBV infection and other cancers.

CONCLUSIONS

HBV infection was potentially associated with an increased risk of gastric cancer. The development mechanism of HBV-associated gastric cancer needs to investigate further.

Hepatitis B virus infection increases the risk of pancreatic cancer: a meta-analysis

OBJECTIVE

The relationship between hepatitis B virus (HBV) and pancreatic cancer has been controversial for years, but more recently new information on this relationship has been updated Therefore, we performed a meta-analysis to provide summary estimates of the risk of pancreatic cancer associated with HBV infection.

METHODS

A systematic literature search on HBV and pancreatic cancer in English was performed in Pubmed, Cochrane library and Embase up to July 2020. Pooled rate ratios (RRs) and 95% confidence intervals (CIs) were calculated by the random-effects model. Stata software version 15.1 was used to perform this meta-analysis of the 17 studies considered to be eligible.

RESULTS

17 studies including 7 case-control and 10 cohort studies met the selection criteria. Begg's and Egger's test results indicated that there was no publication bias. Individuals with Hepatitis B surface antigen (HBsAg) or HBV DNA seropositivity had a significantly increased risk of pancreatic cancer showing an RR (95% CI) of 1.39 (1.19, 1.63). Similar conclusions were drawn from the results of the subgroup analysis (subgroup by study design, population, sex ratio) except when subgrouped by patient's region: the RR and 95% CI in Europe and Oceania were 1.44 (0.88, 2.34) and 1.47(0.38, 5.71) respectively.

CONCLUSIONS

The findings of this meta-analysis suggest that HBV infections may increase the risk of pancreatic cancer under most conditions, while there remains some doubt when comparison is made between European and Oceania patients.

Elevated risk of colorectal, liver, and pancreatic cancers among HCV, HBV and/or HIV (co)infected individuals in a population based cohort in Canada

Introduction:

Studies of the impact of hepatitis C virus (HCV), hepatitis B virus (HBV) and HIV mono and co-infections on the risk of cancer, particularly extra-hepatic cancer, have been limited and inconsistent in their findings.

Methods:

In the British Columbia Hepatitis Testers Cohort, we assessed the risk of colorectal, liver, and pancreatic cancers in association with HCV, HBV and HIV infection status. Using Fine and Gray adjusted proportional subdistribution hazards models, we assessed the impact of infection status on each cancer, accounting for competing mortality risk. Cancer occurrence was ascertained from the BC Cancer Registry.

Results:

Among 658,697 individuals tested for the occurrence of all three infections, 1407 colorectal, 1294 liver, and 489 pancreatic cancers were identified. Compared to uninfected individuals, the risk of colorectal cancer was significantly elevated among those with HCV (Hazard ration [HR] 2.99; 95% confidence interval [CI] 2.55–3.51), HBV (HR 2.47; 95% CI 1.85–3.28), and HIV mono-infection (HR 2.30; 95% CI 1.47–3.59), and HCV/HIV co-infection. The risk of liver cancer was significantly elevated among HCV and HBV mono-infected and all co-infected individuals. The risk of pancreatic cancer was significantly elevated among individuals with HCV (HR 2.79; 95% CI 2.01–3.70) and HIV mono-infection (HR 2.82; 95% CI 1.39–5.71), and HCV/HBV co-infection.

Discussion/Conclusion:

Compared to uninfected individuals, the risk of colorectal, pancreatic and liver cancers was elevated among those with HCV, HBV and/or HIV infection. These findings highlight the need for targeted cancer prevention and diligent clinical monitoring for hepatic and extrahepatic cancers in infected populations.

Research Progress of Pancreas-Related Microorganisms and Pancreatic Cancer

Pancreatic cancer is one of the most common digestive system cancers. Early diagnosis is difficult owing to the lack of specific symptoms and reliable biomarkers. The cause of pancreatic cancer remains ambiguous. Smoking, drinking, new-onset diabetes, and chronic pancreatitis have been proven to be associated with the occurrence of pancreatic cancer. In recent years, a large number of studies have clarified that a variety of microorganisms colonized in pancreatic cancer tissues are also closely related to the occurrence and development of pancreatic cancer, and the specific mechanisms include inflammatory induction, immune regulation, metabolism, and microenvironment changes caused by microorganism. The mechanism of action of the pancreatic colonized microbiome in the tumor microenvironment, as well as immunotherapy approaches require further study in order to find more evidence to explain the complex relationship between the pancreatic colonized microbiome and PDAC. Relevant studies targeting the microbiome may provide insight into the mechanisms of PDAC development and progression, improving treatment effectiveness and overall patient prognosis. In this article, we focus on the research relating to the microorganisms colonized in pancreatic cancer tissues, including viruses, bacteria, and fungi. We also highlight the microbial diversity in the occurrence, invasion, metastasis, treatment, and prognosis of pancreatic cancer in order to elucidate its significance in the early diagnosis and new therapeutic treatment of pancreatic cancer, which urgently need to be improved in clinical practice. The elimination or increase in diversity of the pancreatic microbiome is beneficial for prolonging the survival of PDAC patients, improving the response to chemotherapy drugs, and reducing tumor burden. The colonization of microorganisms in the pancreas may become a new hotspot in the diagnosis and treatment of pancreatic cancer.

Higher Levels of Fibrosis in a Cohort of Veterans with Chronic Viral Hepatitis are Associated with Extrahepatic Cancers

BACKGROUND AND AIMS

An estimated 2.4 million Americans, including more than 150,000 veterans, are chronically infected with hepatitis C virus (HCV). HCV is estimated to cause roughly 25% of all hepatocellular carcinoma. Although its mechanism is unknown, developing evidence suggests that chronic HCV infection is also associated with the development of extrahepatic cancers (EHCs). This paper aims to assess the relationship of hepatic fibrosis and chronic HCV with the risk of developing EHC.

METHODS

We conducted a single-center retrospective chart review of 1541 patients linked to the hepatitis clinic at the Veterans Affairs (VA) Maryland Health Care System who underwent transient elastography for evaluation and management of liver disease from 2014 to 2018. Liver fibrosis was measured using ultrasound and transient elastography. Extrahepatic cancer and site was identified by a retrospective chart review.

RESULTS

In adjusted analysis of EHCs, advanced age (OR: 1.97, 95% CI: 1.30-3.04), and higher measured stiffness (OR 2.19, 95% CI: 1.32-3.64) were associated with an increased likelihood of developing EHC, controlling for HBV infection, HCV exposure, heavy alcohol use, and body mass index.

CONCLUSIONS

We observed a significant association between increasing age and increasing levels of liver fibrosis with increased risk of EHC, notably prostate, head and neck squamous cell, lung, and hematologic cancers.

Bidirectional and dynamic interaction between the microbiota and therapeutic resistance in pancreatic cancer

Pancreatic ductal adenocarcinoma is one of the most lethal malignancies and is known for its high resistance and low response to treatment. Cancer treatments can reshape the microbiota and in turn, the microbiota influences the therapeutic efficacy by regulating immune response and metabolism. This crosstalk is bidirectional, heterogeneous, and dynamic. In this review, we elaborated on the interactions between the microbiota and therapeutic resistance in pancreatic ductal adenocarcinoma. Regulating the microbiota in pancreatic tumor microenvironment may not only generate direct anti-cancer but also synergistic effects with other treatments, providing new directions in cancer therapy.

Viruses in Cancers of the Digestive System: Active Contributors or Idle Bystanders?

The human virome, which is a collection of all the viruses that are present in the human body, is increasingly being recognized as an essential part of the human microbiota. The human gastrointestinal tract and related organs (e.g., liver, pancreas, and gallbladder)-composing the gastrointestinal (or digestive) system-contain a huge number of viral particles which contribute to maintaining tissue homeostasis and keeping our body healthy. However, perturbations of the virome steady-state may, both directly and indirectly, ignite/sustain oncogenic mechanisms contributing to the initiation of a dysplastic process and/or cancer progression. In this review, we summarize and discuss the available evidence on the association and role of viruses in the development of cancers of the digestive system.

Hepatitis C virus infection and risk of pancreatic cancer: A meta-analysis

BACKGROUND

A growing body of evidence has suggested an association between Hepatitis C virus (HCV) infection and risk of pancreatic cancer (PAC). Herein, we conducted a meta-analysis of available evidence to explore this association.

METHODS

We systematically retrieved studies that investigated the association between HCV infection and risk of PAC. Pooled odds ratio (OR) with corresponding 95 % confidence interval (CI) of PAC for patients with HCV infection was calculated using the fixed- or random-effects model.

RESULTS

A total of 16 studies (8 cohort and 8 case-control) were included in this meta-analysis. Combined, patients with HCV infection were more likely to develop PAC than people without it (pooled OR = 1.51, 95 % CI: 1.31, 1.74; I² = 63.49 %, p-value for heterogeneity< 0.001). Studies that adjusted their results for diabetes, chronic pancreatitis, alcohol intake, and smoking showed lower ORs than studies that did not adjust for them.

CONCLUSION

HCV infection was associated with increased risk of PAC, but this association was attenuated among studies that adjusted their results for potential risk factors for PAC. Future prospective cohort studies are needed to confirm this association.

Early Detection of Pancreatic Cancer in Patients With Chronic Liver Disease Under Hepatocellular Carcinoma Surveillance

OBJECTIVE

To evaluate whether patients with hepatitis B virus (HBV)- and hepatitis C virus (HCV)-related chronic liver disease were diagnosed as having pancreatic cancer (PC) at an early stage during abdominal imaging surveillance for hepatocellular carcinoma (HCC).

PATIENTS AND METHODS

We retrospectively examined 447 patients with PC diagnosed at Ehime University Hospital and affiliated centers (2011-2013). Data were collected regarding HBV and HCV status, likelihood of PC diagnosis, and Union for International Cancer Control (UICC) stage. Intergroup comparisons were performed using the χ² test.

RESULTS

The UICC stage distribution in the HCC surveillance group (n=16) was stage 0 (n=2, 12.5%), stage IA (n=3, 18.8%), stage IB (n=2, 12.5%), stage IIA (n=2, 12.5%), stage IIB (n=2, 12.5%), stage III (n=1, 6.3%), and stage IV (n=4, 25%). The UICC stage distribution in the nonsurveillance group (n=431) was stage 0 (n=4, 0.9%), stage IA (n=28, 6.5%), stage IB (n=27, 6.3%), stage IIA (n=86, 20.0%), stage IIB (n=48, 11.1%), stage III (n=56, 13.0%), and stage IV (n=182, 42.2%). The HCC surveillance group had significantly more patients with stage 0 disease than with stages IA through IV (P=.02). Similar results were observed when including stages IA (P=.007) and IB (P=.004) as early stages but not stage IIA (P=.10). A dilated pancreatic duct led to a PC diagnosis in all 6 patients with stage 0 disease.

CONCLUSION

Patients with HBV- and HCV-related chronic liver disease had an early PC diagnosis during HCC surveillance. Careful evaluation of the pancreas is warranted during HCC surveillance.

Environmental Risk Factors of Pancreatic Cancer

Despite the advancement in medical knowledge that has improved the survival rate of many cancers, the survival rate of pancreatic cancer has remained dismal with a five-year survival rate of only 9%. The poor survival of pancreatic cancer emphasizes the urgent need to identify the causes or the risk factors of pancreatic cancer in order to establish effective preventive strategies. This review summarizes the current evidence regarding the environmental (non-genetic, including lifestyle, and clinical factors) risk factors of pancreatic cancer. Based on the current evidence, the established risk factors of pancreatic cancer are cigarette smoking, chronic diabetes, and obesity. Other strong risk factors include low consumption of fruits and vegetables, excess consumption of alcohol, poor oral hygiene, and the lack of allergy history. In the future, more studies are needed to identify additional risk factors of pancreatic cancer, especially the modifiable risk factors that could be included in a public health campaign to educate the public in order to reduce the incidence of pancreatic cancer.

The Microbiota and Pancreatic Cancer

Pancreatic cancer is one of the most lethal diseases. In pancreatic cancer development and progression, genetic (gene mutations and activation of oncogenes) and environmental factors (smoking, alcohol consumption, type 2 diabetes mellitus, obesity) play an essential role. Recently, molecular studies revealed that dysbiosis of microbiota also has influence on cancer development. Research indicates that bacteria and viruses can lead to chronic inflammation, antiapoptotic changes, cell survival, and cell invasion. This review presents bacteria and viruses oncogenic for the pancreas. Possible mechanisms of carcinogenic action are also described.

Helicobacter pylori infection, atrophic gastritis, and risk of pancreatic cancer: A population-based cohort study in a large Japanese population: the JPHC Study

Helicobacter pylori (H. pylori), an established risk factor for gastric cancer, is suggested to also play a role in the development of pancreatic cancer; however, the association remains inconclusive. We examined this association among Japanese men and women. H. pylori and atrophic gastritis (AG) status were determined serologically, using blood sample collected during health checkups. A total of 20,116 subjects enrolled in the Japan Public Health Center-based Prospective Study Cohort II with available data on H. pylori seropositivity (anti-H. pylori) and AG were followed until the end of 2010. Cox proportional hazards models were used to calculate the hazard ratios (HR) and 95% confidence intervals (CI), using the information from the baseline survey. During 320,470 person-years of follow-up, 119 cases of pancreatic cancer were identified. No statically significant increase or decrease in pancreatic cancer risk was observed for H. pylori and AG status, independently or in combination. In a multivariable-adjusted model, we observed a non-significant decrease in the risk among those who had AG but were anti-H. pylori seronegative (HR 0.57, 95% CI 0.31–1.03). In a stratified analysis, we observed a statistically significant increased risk of pancreatic cancer for AG+ (HR 3.64, 95% CI 1.37–9.66), and AG+/anti-H. pylori− or AG+/anti-H. pylori+ (HR 5.21, 95% CI 1.14–23.87) among current smokers. Non-smokers in all categories of AG and anti-H. pylori showed a non-statistical decrease in the risk. There was no statistically significant interaction between H. pylori infection, AG status, and smoking status. Our findings suggest H. pylori seropositivity and AG, individually or in combination, are not associated with the risk of pancreatic cancer in a general Japanese population. Among current smokers, pancreatic cancer risk increased with AG, regardless of H. pylori infection status.

Extrahepatic cancers and chronic HCV infection

Infectious agents, such as HCV, account for ∼15% of human cancers. HCV infects not only hepatocytes but also extrahepatic cells. Chronic HCV infection can induce chronic inflammation with qualitative and quantitative alterations of the immune repertoire and tissue microenvironment, which could induce various neoplasias. Epidemiological studies and meta-analyses suggest an increased rate of extrahepatic cancers in patients with chronic HCV infection along with a higher risk of intrahepatic cholangiocarcinoma, pancreatic cancer and non-Hodgkin lymphoma (NHL), highlighting the need to screen for HCV infection in patients with these cancers. Development of B cell NHL has been associated with HCV infection, with a relative risk of ∼1.5. Direct transformation related to the presence of the virus and chronic antigenic stimulation are the two major non-exclusive mechanisms involved in HCV-related lymphomagenesis. HCV infection alters survival of patients with lymphoma, and sustained virologic response (SVR) substantially improves prognosis. Antiviral treatments might induce remission of indolent lymphoma when SVR is achieved even without chemotherapy, emphasizing the role of HCV in lymphomagenesis in this context. However, studies are needed to provide prospective evidence of a causal relationship between chronic HCV infection and other extrahepatic cancers and to determine whether the risk of extrahepatic cancers is reduced with SVR. In this Review, we report on recent studies analysing the risk of extrahepatic cancers associated with chronic HCV infection. Although there is no doubt regarding the direct and indirect causality between HCV and NHL, an increased risk of other cancers is less clear, with the exception of cholangiocarcinoma.

Hepatitis C Virus and Nonliver Solid Cancers: Is There an Association between HCV and Cancers of the Pancreas, Thyroid, Kidney, Oral Cavity, Breast, Lung, and Gastrointestinal Tract?

Hepatitis C virus (HCV) is known for its oncogenic potential and has been found to be associated with hepatocellular carcinoma (HCC) and non-Hodgkin lymphoma. It has also been postulated that HCV may play a role in the development of other extrahepatic solid tumors of other organs of the body since it has been isolated from the vessel wall, kidney, and oral mucosa. In this article, we have reviewed epidemiological studies that have been done to look into the relationship of HCV with nonliver solid cancers of the pancreas, thyroid, renal, oral cavity, breast, and lung and nonpancreatic gastrointestinal cancers. Based on this review, HCV might be associated with an increased risk of renal cell and lung cancers.

Environmental risk factors for pancreatic cancer: an update

Pancreatic cancer (PC) is one of the most aggressive diseases. Only 10 % of all PC cases are thought to be due to genetic factors. Here, we analyzed the most recently published case-control association studies, meta-analyses, and cohort studies with the aim to summarize the main environmental factors that could have a role in PC. Among the most dangerous agents involved in the initiation phase, there are the inhalation of cigarette smoke, and the exposure to mutagenic nitrosamines, organ-chlorinated compounds, heavy metals, and ionizing radiations. Moreover, pancreatitis, high doses of alcohol drinking, the body microbial infections, obesity, diabetes, gallstones and/or cholecystectomy, and the accumulation of asbestos fibers seem to play a crucial role in the progression of the disease. However, some of these agents act both as initiators and promoters in pancreatic acinar cells. Protective agents include dietary flavonoids, marine omega-3, vitamin D, fruit, vegetables, and the habit of regular physical activity. The identification of the factors involved in PC initiation and progression could be of help in establishing novel therapeutic approaches by targeting the molecular signaling pathways responsive to these stimuli. Moreover, the identification of these factors could facilitate the development of strategies for an early diagnosis or measures of risk reduction for high-risk people.