Helicobacter pylori infection, chronic corpus atrophic gastritis and pancreatic cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort: A nested case-control study

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.

Helicobacter pylori Seropositivity, ABO Blood Type, and Pancreatic Cancer Risk From 5 Prospective Cohorts

BACKGROUND

Helicobacter pylori infection may be a risk factor for pancreatic cancer, particularly infection by strains without the cytotoxin-associated gene A (CagA) virulence factor. Non-O blood type is a known risk factor for pancreatic cancer, and H. pylori gastric colonization occurs largely from bacterial adhesins binding to blood group antigens on gastric mucosa.

METHODS

We included 485 pancreatic cancer cases and 1,122 matched controls from 5 U.S. prospective cohorts. Prediagnostic plasma samples were assessed for H. pylori and CagA antibody titers. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for pancreatic cancer. ABO blood type was assessed using genetic polymorphisms at the ABO gene locus or self-report.

RESULTS

Compared with H. pylori -seronegative participants, those who were seropositive did not demonstrate an increased risk of pancreatic cancer (OR 0.83, 95% CI 0.65-1.06). This lack of association was similar among CagA-seropositive (OR 0.75, 95% CI 0.53-1.04) and -seronegative (OR 0.89, 95% CI 0.65-1.20) participants. The association was also similar when stratified by time between blood collection and cancer diagnosis ( P -interaction = 0.80). Consistent with previous studies, non-O blood type was associated with increased pancreatic cancer risk, but this increase in risk was similar regardless of H. pylori seropositivity ( P -interaction = 0.51).

DISCUSSION

In this nested case-control study, history of H. pylori infection as determined by H. pylori antibody serology was not associated with pancreatic cancer risk, regardless of CagA virulence factor status. The elevated risk associated with non-O blood type was consistent in those with or without H. pylori seropositivity.

Is Helicobacter pylori infection associated with pancreatic cancer? A systematic review and meta-analysis of observational studies

Background and Objectives

Recent observational studies have investigated the association between Helicobacter pylori (H. pylori) infection and pancreatic cancer with conflicting data. Therefore, we conducted a systematic review and meta-analysis to assess the potential association.

Design

This is a systematic review and meta-analysis.

Methods

We searched three databases (PubMed, Embase, and Web of Science) from inception to 30 August 2022. The summary results as odds ratio (OR) or hazard ratio (HR) with 95% confidence interval (CI) were pooled by generic inverse variance method based on random-effects model.

Results

A total of 20 observational studies involving 67,718 participants were included in the meta-analysis. Meta-analysis of data from 12 case-control studies and 5 nested case-control studies showed that there was no significant association between H. pylori infection and the risk of pancreatic cancer (OR = 1.20, 95% CI = 0.95-1.51, p = 0.13). Similarly, we also did not find significant association between cytotoxin-associated gene A (CagA) positive strains, CagA negative strains, vacuolating cytotoxin gene A (VacA) positive strains H. pylori infection, and the risk of pancreatic cancer. Meta-analysis of data from three cohort studies showed that H. pylori infection was not significantly associated with an increased risk of incident pancreatic cancer (HR = 1.26, 95% CI = 0.65-2.42, p = 0.50).

Conclusion

We found insufficient evidence to support the proposed association between H. pylori infection and increased risk of pancreatic cancer. To better understand any association, future evidence from large, well-designed, high-quality prospective cohort studies that accounts for diverse ethnic populations, certain H. pylori strains, and confounding factors would be useful to settle this controversy.

A rare case of giant panda cancer: Pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant cancer of the digestive system common among humans. However, it is rarely reported in wild animals. In 2018, a giant panda died in the Beijing Zoo. During subsequent histological observation of the pancreas, it was discovered that the glandular epithelial cells had lost the pancreatic acinar structure, tubular areas with obvious structure in the pancreas, and the ductal epithelium was substituted by high columnar mucus cells. Masson staining showed that there were several fibrous tissue proliferative reactions around the ductal adenocarcinoma and immunohistochemical staining revealed that CK7 and CK19 were positively expressed in the pancreatic tissue. Therefore, the pathological diagnosis indicated that the panda had PDAC. In this paper, the panda's living conditions and pathological diagnosis results are examined, with the aim of providing a reference point for the future diagnosis of wild animal tumors.

Association Between Helicobacter pylori Infection and the Risk of Pancreatic Cancer: A Systematic Review Based on Observational Studies

Helicobacter pylori (H. pylori) bacterial infection has long been scrutinized as one of the potential risk factors for the development of pancreatic cancer with quite inconsistent and unequivocal data. Little is known about the risk factors involved with this malignancy. In this systematic review, we aimed to examine the relationship between H. pylori infection and pancreatic cancer based on the evidence from the existing observational studies across the world. We searched major electronic databases such as PubMed, MEDLINE, Science Direct, and Cochrane Library. After a careful and thorough screening process, we selected 15 observation studies for this systematic review. Six of 15 studies found a significant association between H. pylori infection and pancreatic cancer. Additionally, four of these studies found a significant relationship between the cytotoxin-associated gene A strain of H. pylori and pancreatic cancer. Based on the evidence from the selected studies, a weak association was observed between H. pylori infection and cancer of the pancreas, especially in European and Asian populations compared to the North American population. The cross-sectional evidence from the case-control studies only suggests the existence of an association but does not provide substantial evidence of the causative relationship. Further large-scale, prospective cohort studies are warranted in the future to understand this contradictory relationship better.

Association of the Microbiota and Pancreatic Cancer: Opportunities and Limitations

The human body is thoroughly colonized by a wide variety of microorganisms, termed microbiota. Pancreatic cancer, one of the most aggressive forms of cancer, is no exception. The microbiota of pancreatic cancer largely influences and even dominates the occurrence, development and outcome of pancreatic cancer in many ways. Studies have shown that microbiota could change the malignant phenotype and prognosis of pancreatic cancer by stimulating persistent inflammation, regulating the antitumor immune system, changing the tumor microenvironment and affecting cellular metabolism. This is why the association of the microbiota with pancreatic cancer is an emerging area of research that warrants further exploration. Herein, we investigated the potential microbial markers of pancreatic cancer, related research models, the mechanism of action of microbiota in pancreatic cancer, and pancreatic cancer-microbiota-related treatment.

Gastric Mucosal Abnormality and Risk of Pancreatic Cancer: A Population-Based Gastric Biopsy Cohort Study in Sweden

BACKGROUND

It remains open whether gastric precancerous lesions are associated with an elevated risk of pancreatic cancer. Our aim was to investigate the association between gastric mucosal status and pancreatic cancer risk.

METHODS

Patients with gastric biopsies [normal, minor changes, superficial gastritis, and atrophic gastritis/intestinal metaplasia/dysplasia (AG/IM/Dys)] from the Swedish histopathology registers during 1979 to 2011 were included. Cross-linkages with several nationwide registries allowed complete follow-up and identification of pancreatic cancer cases until 2014. Standardized incidence ratios (SIR) and HRs were estimated.

RESULTS

During 3,438,248 person-years of follow-up with 318,653 participants, 3,540 cases of pancreatic cancer were identified. The same pattern of excess risk of pancreatic cancer compared with the general population was observed across all groups: a peak of 12- to 21-fold excess risk in the first year after biopsy [e.g., normal: SIR = 17.4; 95% confidence interval (CI), 15.7-19.3; AG/IM/Dys: SIR = 11.5; 95% CI, 9.9-13.4], which dropped dramatically during the second and third years, followed by 20% to 30% increased risk after the third year (e.g., normal: SIR = 1.2; 95% CI, 1.1-1.4; AG/IM/Dys: SIR = 1.3; 95% CI, 1.1-1.5). However, no significant excess risk was observed with the normal gastric mucosa as reference.

CONCLUSIONS

This unique, large pathologic cohort study did not find evidence that abnormal gastric mucosal status is causally associated with a long-term pancreatic cancer risk. However, a highly increased short-term risk was observed for people undergoing gastroscopy with biopsy sampling compared with the general population.

IMPACT

Further studies for a long-term risk of pancreatic cancer in patients with gastric biopsies are needed, with further adjustments.

Helicobacter pylori infection and other bacteria in pancreatic cancer and autoimmune pancreatitis

Helicobacter pylori (H. pylori) is an infectious agent influencing as much as 50% of the world’s population. It is the causative agent for several diseases, most especially gastric and duodenal peptic ulcer, gastric adenocarcinoma and mucosa-associated lymphoid tissue lymphoma of the stomach. A number of other, extragastric manifestations also are associated with H. pylori infection. These include neurological disorders, such as Alzheimer’s disease, demyelinating multiple sclerosis and Parkinson’s disease. There is also evidence for a relationship between H. pylori infection and such dermatological diseases as psoriasis and rosacea as well as a connection with infection and open-angle glaucoma. Generally little is known about the relationship between H. pylori infection and diseases of the pancreas. Most evidence about H. pylori and its potential role in the development of pancreatic diseases concerns pancreatic adenocarcinoma and autoimmune forms of chronic pancreatitis. There is data (albeit not fully consistent) indicating modestly increased pancreatic cancer risk in H. pylori-positive patients. The pathogenetic mechanism of this increase is not yet fully elucidated, but several theories have been proposed. Reduction of antral D-cells in H. pylori-positive patients causes a suppression of somatostatin secretion that, in turn, stimulates increased secretin secretion. That stimulates pancreatic growth and thus increases the risk of carcinogenesis. Alternatively, H. pylori, as a part of microbiome dysbiosis and the so-called oncobiome, is proven to be associated with pancreatic adenocarcinoma development via the promotion of cellular proliferation. The role of H. pylori in the inflammation characteristic of autoimmune pancreatitis seems to be explained by a mechanism of molecular mimicry among several proteins (mostly enzymes) of H. pylori and pancreatic tissue. Patients with autoimmune pancreatitis often show positivity for antibodies against H. pylori proteins. H. pylori, as a part of microbiome dysbiosis, also is viewed as a potential trigger of autoimmune inflammation of the pancreas. It is precisely these relationships (and associated equivocal conclusions) that constitute a center of attention among pancreatologists, immunologists and pathologists. In order to obtain clear and valid results, more studies on sufficiently large cohorts of patients are needed. The topic is itself sufficiently significant to draw the interest of clinicians and inspire further systematic research. Next-generation sequencing could play an important role in investigating the microbiome as a potential diagnostic and prognostic biomarker for pancreatic cancer.

A review of lifestyle and environment risk factors for pancreatic cancer

Pancreatic cancer (PaCa) is one of the deadliest cancers known and its incidence is increasing in the developed countries. Because of the lack of biomarkers that allow early detection and the tendency of the disease to be asymptomatic, the diagnosis comes often too late for effective surgical or chemotherapy intervention. Lifestyle factors, that may cause common genetic modifications occurring in the disease, interfere with pancreatic physiology or function, and play a role in PaCa development, have been of concern recently, since a strategy to prevent this severe cancer is needed. This review identifies the latest evidences related to increased risk of developing PaCa due to dietary habits such as high alcohol, fructose and red or processed meat intake, and pathological conditions such as diabetes, obesity and infections in addition to stress and smoking behaviour. It aims to highlight the importance of intervening on modifiable risk factors: the action on these factors could prevent a considerable number of new cases of PaCa.

The potential role of bacteria in pancreatic cancer: a systematic review

Pancreatic cancer is a lethal and devastating disease in the worldwide. Recognized risk factors for pancreatic cancer include cigarette smoking, obesity, type II diabetes and chronic pancreatitis. Other factors such as variant ABO blood type and Helicobacter pylori may also play an important role in pancreatic carcinogenesis. Recently, growing evidence suggests that the association between bacteria and pancreatic cancer is positive and related immune/inflammation activation and increased nitrosamine exposure may be its potential mechanism. Interestingly, it is debatable whether the relationship of bacteria and pancreatic cancer is causative, reactive or parallel and future studies are in progress. Here we review recent progress in pancreatic cancer and its related bacteria.

Demystifying the manipulation of host immunity, metabolism, and extraintestinal tumors by the gut microbiome

The trillions of microorganisms in the gut microbiome have attracted much attention recently owing to their sophisticated and widespread impacts on numerous aspects of host pathophysiology. Remarkable progress in large-scale sequencing and mass spectrometry has increased our understanding of the influence of the microbiome and/or its metabolites on the onset and progression of extraintestinal cancers and the efficacy of cancer immunotherapy. Given the plasticity in microbial composition and function, microbial-based therapeutic interventions, including dietary modulation, prebiotics, and probiotics, as well as fecal microbial transplantation, potentially permit the development of novel strategies for cancer therapy to improve clinical outcomes. Herein, we summarize the latest evidence on the involvement of the gut microbiome in host immunity and metabolism, the effects of the microbiome on extraintestinal cancers and the immune response, and strategies to modulate the gut microbiome, and we discuss ongoing studies and future areas of research that deserve focused research efforts.

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.

Body site-dependent variations of microbiota in pancreatic cancer pathophysiology

Lack of specific symptoms and reliable biomarkers, along with aggressive nature and resistance to therapies makes pancreatic cancer (PC) one of the leading causes of death from cancer worldwide. The search for new diagnostic, prognostic, predictive, and therapeutic tools that could improve clinical outcomes of patients has led, in recent years, to the investigation of potential roles for the microbiota in the pathogenesis of this disease. The human microbiota encompasses trillions of microorganisms residing within several body tissues and organs, where they provide beneficial functions for host homeostasis and health. Derangements of the microbial ecology in different anatomic districts have been described in PC, as in many other diseases, both in patients and in animal models. In detail, infection from the gastric pathogen Helicobacter pylori and changes in composition and diversity of oral, intestinal, and pancreatic microbiota have been found to associate with PC. Future research should assess how to potentially exploit such differences in microbiota composition as diagnostic, prognostic, or predictive biomarkers, and as targets for therapeutic interventions, in the hope of improving the dismal prognosis of this insidious cancer.

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.

The Microbiome and Pancreatic Cancer: An Evidence-based Association?

Many risk factors for pancreatic cancer are related with microbiome alteration. In the past few years, the human microbiome and its relation with the immune system have been linked with carcinogenesis of different organs distant from the gut, including the pancreas. Patterns of oral microbiome associated with periodontitis are associated with an increased risk of pancreatic cancer, possibly because of the increased systemic inflammatory response, or to the capacity of some specific bacteria to alter the host immune response, making it more favorable to cancer cells. Helicobacter pylori infection when affecting the gastric body mucosa with subsequent hypochlorhydria also seems associated with an increased risk of pancreatic cancer. The composition of the intestinal microbiome is different in animal models and in humans with pancreatic cancer who have a distinct microbiome population compared with controls. Some specific bacteria can migrate from the intestine to the pancreas, and their ablation restores the immune system activity through its reprogramming with a switch toward a Th1 response and displays a protective effect toward tumor growth. More research in this area might lead to progress in terms of pancreatic cancer prevention and treatment, possibly in association with immunotherapy.

[Epidemiology of pancreatic cancer]

Actually, pancreatic cancer is a major challenge in digestive oncology. Its prognosis remains very poor with a five-year net survival less than 10%. Although if pancreatic cancer incidence was low, data from French digestive cancer registries show a dramatic increase in recent years, more marked in women (annual variation of +3.6% between 1982 and 2012) than in men (+2.3%). The currently recognized risk factors like tobacco or obesity cannot explain this evolving epidemiology. Moreover, progress in understanding pancreatic carcinogenesis is still insufficient. Except for familial aggregation, systematic screening couldn't be proposed.

Helicobacter pylori, gastric cancer and other gastrointestinal malignancies

In a retrospective study performed in California, U.S.A., ca. 3% of patients with gastric intestinal metaplasia (GIM) developed gastric cancer (GC) within a median time period of 4.6 years after diagnosis of GIM. This observation stresses the importance of targeted surveillance even in regions with a low GC prevalence. Patients with alcoholic liver disease as well as survivors of colorectal and lobular breast cancer were found to be at increased risk of secondary GC. A population-based Chinese study confirmed "serologic biopsy" as a useful screening tool for stratifying the individual risk of developing GC. Concerning GC therapy, a post hoc analysis of the MAGIC trial reported that regression of lymph node metastases, but not the tumor regression itself, predicts overall survival. Furthermore, in patients with high microsatellite instable tumors, perioperative chemotherapy leads to an increased risk of mortality. Two studies confirmed that eradication therapy is worthwhile as an initial treatment for gastric mucosa-associated lymphoid tissue (MALT) lymphoma irrespective of the H. pylori infection status and stage. An increased risk of a second primary malignancy including GC was observed in these patients treated with immuno/chemotherapy but not in patients treated solely with an H. pylori eradication treatment. With respect to gastrointestinal malignancies other than GC, discrepant data have been published regarding the association of H. pylori with pancreatic cancer whereas no association has been reported with esophageal squamous cell carcinoma. The majority of published studies still support an association of H. pylori with colon neoplasms.

Helicobacter pylori infection, atrophic gastritis, and pancreatic cancer risk: A meta-analysis of prospective epidemiologic studies

BACKGROUND

To investigate the associations of Helicobacter pylori (Hp) infection and atrophic gastritis (AG) with pancreatic cancer risk.

METHODS

A literature search in PubMed was performed up to July 2017. Only prospective cohort and nested case-control studies enrolling cancer-free participants were eligible. Incident pancreatic cancer cases were ascertained during the follow-up. The risks of pancreatic cancer were compared between persons infected and noninfected with Hp, or between those with and without AG status at baseline. Odds ratios (ORs) or hazard ratios were combined. Subgroup and sensitivity analyses were performed, and publication bias was estimated.

RESULTS

Three cohort studies and 6 nested case-control studies, including 65,155 observations, were analyzed. The meta-analyses did not confirm the association between pancreatic cancer risk and Hp infection (OR = 1.09, 95% confidence interval [CI] = 0.81-1.47) or AG status (OR = 1.18, 95% CI = 0.80-1.72). However, particular subpopulations potentially had increased risks of pancreatic cancer. Cytotoxin-associated gene A (CagA)-negative strains of Hp might be a causative factor of pancreatic cancer (OR = 1.30, 95% CI = 1.05-1.62), but a sensitivity analysis by leave-one-out method did not fully warrant it (OR = 1.20, 95% CI = 0.93-1.56). In 1 nested case-control study, AG at stomach corpus in Hp-negative subpopulation might have increased risk of pancreatic cancer, but with a poor test power = 0.56. Publication biases were nonsignificant in the present meta-analysis.

CONCLUSION

Based on current prospective epidemiologic studies, the linkage of pancreatic cancer to Hp infection or AG status was not warranted on the whole. Nevertheless, prospective studies only focusing on those specific subpopulations are further required to obtain better power.