Molecular identification of Helicobacter DNA present in human colorectal adenocarcinomas by 16S rDNA PCR amplification and pyrosequencing analysis

Helicobacter pylori infection is associated with the development of sporadic colorectal carcinoma and colorectal adenomatous polyps

Helicobacter pylori (H. pylori) infection is a well-established carcinogen that has been extensively studied in the context of gastric diseases. Recent studies suggested a potential association between H. pylori and the risk of colorectal carcinoma (CRC). However, available data remains insufficient to definitively establish a causal relationship between H. pylori infection and the development of CRC and its precursor lesions. In our study, we reviewed all patients diagnosed with CRC in 2020 at our institution. H. pylori assessment was performed in all 92 CRC specimens by immunohistochemistry. Notably, two of the three patients detected with H. pylori infection are under the age of 50. Subsequently, we reviewed a total of 52 patients under the age of 50 diagnosed with CRC at our institution from 2015 to 2022. Among these patients, H. pylori infection was detected in 7 CRC specimens (13.46 %). All seven patients had adenocarcinoma on the left side of the colon. In exploring the link between H. pylori infection and the risk of developing CRC precursor lesions, we analyzed 242 patients who underwent colonoscopy guided polypectomy and also had stomach biopsies from 2015 to 2022. Of these patients, 21 were proved to be positive for H. pylori infection in the stomach, while the remaining 221 were negative. Among the H. pylori-positive group, 76.19 % (16 patients) exhibited adenomatous polyps, compared to 33.48 % (74 patients) in the H. pylori-negative patients (p=0.0001). However, no H. pylori was detected in any colonic adenomatous polyps. Our findings contribute additional evidence supporting the association between H. pylori infection and the development of sporadic CRC, probably a particular association with early-onset ones. Furthermore, gastric H. pylori infection appears to be linked to the higher prevalence of colonic adenomatous polyps, suggesting that individuals with gastric H. pylori infection may benefit from closer and earlier monitoring through colonoscopy.

Effect of Trace Element Selenium on the Intestinal Microbial Community in Nude Mice with Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer worldwide. The role of intestinal microbiota in carcinogenesis has also become an important research topic, and CRC is closely related to the intestinal microbiota. Selenium-containing compounds have attracted more attention as anticancer drugs as they can have minimal side effects. The purpose of this study was to determine and compare the effect of sodium selenite and selenomethionine on the microbial communities of nude mice with CRC. A CRC ectopic tumorigenesis model was established by subcutaneously injecting HCT116 cells into nude mice. The mice were then intraperitoneally injected with sodium selenite and selenomethionine for 24 days to regulate their intestinal microbiota. Compared with sodium selenite, selenomethionine resulted in a greater reduction in the richness and diversity of intestinal microbiota in nude mice with CRC, and the richness and diversity were closer to healthy levels. Selenomethionine also regulated a wider variety of flora. Additionally, sodium selenite and selenomethionine produced different microorganisms, changed function and metabolic pathways in the intestinal microbiota. Both sodium selenite and selenomethionine have certain effects on restoring the intestinal microbial diversity in nude mice with CRC, and the effect of selenomethionine is better than that of sodium selenite.

Impact of Helicobacter pylori Infection and Treatment on Colorectal Cancer in a Large, Nationwide Cohort

PURPOSE

Helicobacter pylori is the most common cause of infection-associated cancer worldwide. We aimed to evaluate the impact of H. pylori infection and treatment on colorectal cancer (CRC) incidence and mortality.

PATIENTS

US Veterans who completed H. pylori testing between 1999 and 2018.

METHODS

We conducted a retrospective cohort analysis among adults within the Veterans Health Administration who completed testing for H. pylori. The primary exposures were (1) H. pylori test result (positive/negative) and (2) H. pylori treatment (untreated/treated) among H. pylori-positive individuals. The primary outcomes were CRC incidence and mortality. Follow-up started at the first H. pylori testing and continued until the earliest of incident or fatal CRC, non-CRC death, or December 31, 2019.

RESULTS

Among 812,736 individuals tested for H. pylori, 205,178 (25.2%) tested positive. Being H. pylori-positive versus H. pylori-negative was associated with higher CRC incidence and mortality. H. pylori treatment versus no treatment was associated with lower CRC incidence and mortality (absolute risk reduction 0.23%-0.35%) through 15-year follow-up. Being H. pylori-positive versus H. pylori-negative was associated with an 18% (adjusted hazard ratio [adjusted HR], 1.18 [95% CI, 1.12 to 1.24]) and 12% (adjusted HR, 1.12 [95% CI, 1.03 to 1.21]) higher incident and fatal CRC risk, respectively. Individuals with untreated versus treated H. pylori infection had 23% (adjusted HR, 1.23 [95% CI, 1.13 to 1.34]) and 40% (adjusted HR, 1.40 [95% CI, 1.24 to 1.58]) higher incident and fatal CRC risk, respectively. The results were more pronounced in the analysis restricted to individuals with nonserologic testing.

CONCLUSION

H. pylori positivity may be associated with small but statistically significant higher CRC incidence and mortality; untreated individuals, especially those with confirmed active infection, appear to be most at risk.

Relationship between Helicobacter pylori infection and colorectal polyp/colorectal cancer

Helicobacter pylori (H. pylori) plays an important role in the development of gastric cancer, although its association to colorectal polyp (CP) or colorectal cancer (CRC) is unknown. In this issue of World Journal of Gastrointestinal Surgery, Zhang et al investigated the risk factors for H. pylori infection after colon polyp resection. Importantly, the researchers used R software to create a prediction model for H. pylori infection based on their findings. This editorial gives an overview of the association between H. pylori and CP/CRC, including the clinical significance of H. pylori as an independent risk factor for CP/CRC, the underlying processes of H. pylori-associated carcinogenesis, and the possible risk factors and identification of H. pylori.

Effects of Helicobacter pylori infection on intestinal microbiota, immunity and colorectal cancer risk

Infecting about half of the world´s population, Helicobacter pylori is one of the most prevalent bacterial infections worldwide and the strongest known risk factor for gastric cancer. Although H. pylori colonizes exclusively the gastric epithelium, the infection has also been associated with various extragastric diseases, including colorectal cancer (CRC). Epidemiological studies reported an almost two-fold increased risk for infected individuals to develop CRC, but only recently, direct causal and functional links between the chronic infection and CRC have been revealed. Besides modulating the host intestinal immune response, H. pylori is thought to increase CRC risk by inducing gut microbiota alterations. It is known that H. pylori infection not only impacts the gastric microbiota at the site of infection but also leads to changes in bacterial colonization in the distal large intestine. Considering that the gut microbiome plays a driving role in CRC, H. pylori infection emerges as a key factor responsible for promoting changes in microbiome signatures that could contribute to tumor development. Within this review, we want to focus on the interplay between H. pylori infection, changes in the intestinal microbiota, and intestinal immunity. In addition, the effects of H. pylori antibiotic eradication therapy will be discussed.

No evident causal association between Helicobacter pylori infection and colorectal cancer: a bidirectional mendelian randomization study

Observational studies have reported a correlation between Helicobacter pylori infection and colorectal cancer (CRC); however, the underlying cause has remained unclear. This research was aimed at determining whether there is a correlation between H. pylori infection and CRC by measuring the prevalence of H. pylori CagA antibodies and VacA antibodies. Using data from many genome-wide association studies (GWAS), we conducted a Mendelian randomization (MR) study with two sample GWAS. Then, we used bidirectional MR to evaluate the association between H. pylori infection and CRC for identifying causation. The most common method of analysis was the inverse variance-weighted technique. In addition, we performed supplementary analyses using the weighted median technique and MR-Egger regression. Horizontal pleiotropic outliers were identified and corrected using the MR Pleiotropy RESidual Sum and Outlier (MR-PRESSO) method. Genetically predicted anti-H. pylori IgG seropositivity was not causally associated with CRC [odds ratio (OR): 1.12; 95% confidence interval (CI): 0.98-1.27, P = 0.08] and neither were H. pylori VacA antibody levels (OR = 0.96, 95% CI: 0.90-1.02, P = 0.25) or H. pylori CagA antibody levels (OR = 1.00, 95% CI: 0.93-1.07, P = 0.92). Furthermore, reverse MR analysis did not reveal evidence for a causal effect of CRC on H. pylori infection. The weighted median, the MR-Egger method, and MR-PRESSO yielded identical results. Using genetic data, MR analysis showed there was no evidence for a causal association between seroprevalence of H. pylori infection and CRC. The relationship between H. pylori infection and CRC requires further research.

Carcinogenic microbiota and its role in colorectal cancer development

Colorectal cancer (CRC) is one of the most common malignancies worldwide. The main risk factors for CRC are family history of colon or rectal cancer, familial polyposis syndrome or hereditary nonpolyposis, and chronic inflammatory bowel diseases (ulcerative colitis and Crohn's disease). Recent studies show that the gastrointestinal microbiota play a significant role in colorectal carcinogenesis. In this review we present the microorganisms, whose influence on the development of CRC has been proven: Bacteroides fragilis, Clostridioides and Clostridium spp., Enterococcus faecalis, Escherichia coli, Fusobacterium nucleatum, Helicobacter pylori, Peptostreptococcus anaerobius, Streptococcus bovis group, and sulfate-reducing bacteria. Moreover, the carcinogenic mechanisms of action mediated by the above bacteria are laid out.

Biological roles of toll-like receptors and gut microbiota in colorectal cancer

Colorectal cancer (CRC) is one of the most considerably common malignancies of the alimentary system, with high mortality and incidence rates.  The present study suggested that the occurrence of CRC is closely related to bacteria, as the large intestine is a gathering place for human micro-organisms. However, the nosogenesis of bacteria leading to tumorigenesis is still obscure. Recently, many studies have reported that toll-like receptors and their related molecular pathways are involved in the process of gut micro-organisms generating CRC. Gut micro-organisms can promote or inhibit the development of CRC via binding to special toll-like receptors. In this paper, the authors review the relationship among toll-like receptors, gut micro-organisms and CRC in order to provide a reference for future tumor immunotherapy and targeted therapy.

The relationship between colorectal cancer and gastric histopathology: case-control study

Aim: The aim of this study was to investigate the gastric histopathological findings (Helicobacter pylori (H. pylori), intestinal metaplasia (IM), atrophic gastritis (AG), and dysplasia) in the patients with and without colorectal cancer (CRC). Material and Method: Two hundred ninety five patients (160 CRC patients and 135 control individuals) were included in the study. Gastric histopathological findings of the patients who underwent upper gastrointestinal (GI) endoscopy were analyzed retrospectively. Results: H. pylori positivity and IM rates in the CRC patient group were significantly higher than the control group (58.8%&27.8% and 33.1%&19.5%, p<0.001 and p<0.012, respectively). In addition, AG, lymphoplasmocytic infiltration, and dysplasia rates were also higher in the CRC patients compared to the control group. But, they were not statistically significant (p=0.462, p=0.103, and p=0.195, respectively). Conclusion: In our study, the frequency of H. pylori and IM in patients with CRC was higher than in the control group. Since the prevalence of H. pylori infection is high in Turkey and H. pylori-related gastric diseases may be potential risk factors for colorectal neoplasia, it is recommended that individuals in the high-risk group to be screened for colonoscopy. Also, upper GI endoscopic examination should be performed to screen for gastric premaling lesions in patients with CRC.

Effects of Helicobacter pylori infection in gastrointestinal tract malignant diseases: From the oral cavity to rectum

Helicobacter pylori (H. pylori) has infected approximately fifty percent of humans for a long period of time. However, improvements in the public health environment have led to a decreased chance of H. pylori infection. However, a high infection rate is noted in populations with a high incidence rate of gastric cancer (GC). The worldwide fraction of GC attributable to H. pylori is greater than 85%, and a high H. pylori prevalence is noted in gastric mucosa-associated lymphoid tissue lymphoma patients. These results indicate that the majority of GC cases can be prevented if H. pylori infection is eliminated. Because H. pylori exhibits oral-oral or fecal-oral transmission, the relationship between this microorganism and other digestive tract malignant diseases has also attracted attention. This review article provides an overview of H. pylori and the condition of the whole gastrointestinal tract environment to further understand the correlation between the pathogen and the host, thus allowing improved realization of disease presentation.

Periodontitis, Helicobacter pylori infection, and gastrointestinal tract cancer mortality

AIM

Periodontitis has been proposed to lead to Helicobacter pylori infection, which could cause many gastrointestinal tract cancers. This study aimed to determine the association or otherwise between periodontitis and survival outcomes in individuals with respect to H. pylori infection.

MATERIALS AND METHODS

The study population comprised 4955 subjects aged 20-90 who had received both periodontal examination and H. pylori serum test in the Third National Health and Nutrition Examination Survey (NHANES III) database. Logistic regression models were used to analyse the association between periodontitis and H. pylori seropositivity (H. pylori infection). Survival analysis was performed using the NHANES III linked to mortality data. Cox proportional hazard regression was carried out to investigate the association between periodontitis and gastrointestinal tract cancer mortality in individuals with/without H. pylori infection.

RESULTS

Compared to periodontal health, periodontitis was significantly associated with increased odds of H. pylori infection (OR = 1.271, 95% CI = 1.177-1.372). Periodontitis significantly increased the mortality risk from all causes (HR = 1.574, 95% CI = 1.327-1.866) and all cancers (HR = 1.948, 95% CI = 1.701-2.232), including gastrointestinal (GI) tract cancer (HR = 4.140, 95% CI = 3.656-4.687), gastric cancer (HR = 4.288, 95% CI = 3.969-4.632), and colorectal cancer (HR = 4.814, 95% CI = 3.849-6.020) in subjects with H. pylori infection after adjusting for health-related factors. Periodontitis was significantly related to the decreased survival time in subjects with GI tract (p = .001) or colorectal cancer (p = .002) and H. pylori infection.

CONCLUSION

Our study demonstrated that periodontitis was significantly associated with higher mortality risk of GI tract, gastric, and colorectal cancer in subjects with H. pylori infection. Owing to an interactive effect between periodontitis and H. pylori infection on cancer mortality, H. pylori infection has a significant moderating effect in regulating the association between periodontitis and mortality due to all cancers, including GI tract cancer and colorectal cancer.

Helicobacters and cancer, not only gastric cancer?

The Helicobacter genus actually comprises 46 validly published species divided into two main clades: gastric and enterohepatic Helicobacters. These bacteria colonize alternative sites of the digestive system in animals and humans, and contribute to inflammation and cancers. In humans, Helicobacter infection is mainly related to H. pylori, a gastric pathogen infecting more than half of the world's population, leading to chronic inflammation of the gastric mucosa that can evolve into two types of gastric cancers: gastric adenocarcinomas and gastric MALT lymphoma. In addition, H. pylori but also non-H. pylori Helicobacter infection has been associated with many extra-gastric malignancies. This review focuses on H. pylori and its role in gastric cancers and extra-gastric diseases, as well as malignancies induced by non-H. pylori Helicobacters. Their different virulence factors and their involvement in carcinogenesis is discussed. This review highlights the importance of both gastric and enterohepatic Helicobacters in gastrointestinal and liver cancers.

Gut Microbiota Dysbiosis Drives the Development of Colorectal Cancer

BACKGROUND

The gut microbiota is a diverse community of microbes that maintain the stability of the intestinal environment. Dysbiosis of the gut microbiota has been linked to gastrointestinal diseases, such as colorectal cancer (CRC) - a leading cause of death for cancer patients.

SUMMARY

Candidate pathogens have been identified using bacterial culture and high-throughput sequencing techniques. Currently, there is evidence to show that specific intestinal microbes drive CRC development and progression, yet their pathogenic mechanisms are still unclear. Key Messages: In this review, we describe the known healthy gut microbiota and its changes in CRC. We especially focus on exploring the pathogenic mechanisms of gut microbiota dysbiosis in CRC. This is crucial for explaining how gut microbiota dysbiosis drives the process of colorectal carcinogenesis and tumor progression. Evaluation of changes in the gut microbiota during CRC development and progression offers a new strategy for the diagnosis and treatment of this disease.

Tripartite relationship between gut microbiota, intestinal mucus and dietary fibers: towards preventive strategies against enteric infections

The human gut is inhabited by a large variety of microorganims involved in many physiological processes and collectively referred as to gut microbiota. Disrupted microbiome has been associated with negative health outcomes and especially could promote the onset of enteric infections. To sustain their growth and persistence within the human digestive tract, gut microbes and enteric pathogens rely on two main polysaccharide compartments, namely dietary fibers and mucus carbohydrates. Several evidences suggest that the three-way relationship between gut microbiota, dietary fibers and mucus layer could unravel the capacity of enteric pathogens to colonise the human digestive tract and ultimately lead to infection. The review starts by shedding light on similarities and differences between dietary fibers and mucus carbohydrates structures and functions. Next, we provide an overview of the interactions of these two components with the third partner, namely, the gut microbiota, under health and disease situations. The review will then provide insights into the relevance of using dietary fibers interventions to prevent enteric infections with a focus on gut microbial imbalance and impaired-mucus integrity. Facing the numerous challenges in studying microbiota-pathogen-dietary fiber-mucus interactions, we lastly describe the characteristics and potentialities of currently available in vitro models of the human gut.

Helicobacter pylori and colorectal neoplasms: a concise review

Helicobacter pylori is the main etiological agent of all malignant tumors caused by an infectious disease. It is a major, at times dominant, factor in the pathogenesis of a large spectrum of diseases such as acute and chronic gastritis, gastric and duodenal ulcers, gastric carcinoma, and lymphoma. Epidemiological and experimental studies suggest that H. pylori chronic infection may be related to different extragastric diseases, including colorectal neoplasms. This concise review aims to explore the association of H. pylori infection with colorectal cancer and adenoma, including the recent epidemiological findings, the diagnostic methods employed to detect H. pylori and virulent factors, and the potentially involved mechanisms. Furthermore, is attempted to establish the current data integration for causal inference using the Bradford-Hill causality criteria. The weak, although global, strength of the epidemiological positive association between H. pylori infection and colonic neoplasms associated to new mechanisms postulated to explain this interaction, including intestinal dysbiosis, should stimulate future studies. Prospective confirmatory studies to establish the role of H. pylori eradication in the process of carcinogenic transformation of the colonic epithelium may define its eventual role in the treatment and prevention of colonic neoplasms.

Microbial Characteristics of Locally Advanced Rectal Cancer Patients After Neoadjuvant Chemoradiation Therapy According to Pathologic Response

Background

Intestinal microbiota play a critical role in the development of colorectal cancer. However, little is known about the structure and characteristics of gut microbial in colorectal cancer, especially in locally advanced rectal cancer after neoadjuvant chemoradiation therapy.

Methods

Here, we performed this study to evaluate microbial characteristics between pathologic complete response (pCR) (n=12) and non-pathological complete response (Non-pCR) (n=45) tumor tissues from patients with locally advanced rectal cancer after neoadjuvant chemoradiation therapy. In this study, 16S rRNA gene sequencing was used to detect the microbial diversity including Alpha diversity and Beta diversity. Moreover, we used PICRUSt from the Kyoto Encyclopedia of Genes and Genomes (KEGG) database to predict the microbial metabolism functions.

Results

There was significant statistical difference in PFS between pCR and Non-pCR group (p < 0.05). However, there was no significant difference in OS between pCR and Non-pCR group. The microbial compositions in the both groups were Proteobacteria, Actinobacteria, Firmicutes and Thermi and Bacteroidetes at the phylum level. The five most predominant genera in both pCR and Non-pCR tissue groups were Sphingobium, Acinetobacter, Cupriavidus, Thermi and Sphingomonas at the genus level. The key taxa identified in the pCR and Non-pCR tissues were Thermi and Sphingomonadaceae respectively. In addition, a series of human disease-related genes were also significantly different between pCR and Non-pCR group.

Conclusion

In summary, we demonstrated the characteristic differences in microbial communities between pCR tissues and Non-pCR tumor tissues from locally advanced rectal cancer patients after neoadjuvant chemoradiation therapy. Our results present new alterations in the microbiome in locally advanced rectal cancer after neoadjuvant chemoradiation therapy, suggesting that it will provide a new perspective for the precise treatment of neoadjuvant rectal cancer by targeting specific microbial species in the future.

Helicobacter pylori Infection and the Development of Advanced Colorectal Neoplasia

BACKGROUND

An association between Helicobacter pylori infection and colorectal neoplasia has been reported in cross-sectional studies.

GOALS

We examined the association between H. pylori infection and the development of advanced colorectal neoplasia (AN) in a screening cohort.

STUDY

We identified 3753 adults, who underwent screening and subsequent surveillance colonoscopies. The primary outcome was the development of metachronous AN, as confirmed by surveillance colonoscopy. H. pylori infection status was assessed by an H. pylori-specific immunoglobulin G antibody test. Sensitivity analysis was also performed by H. pylori infection status on the basis of histology.

RESULTS

During a median follow-up of 41 months, the incidence of AN was 3.2% and 1.7% in participants with and without H. pylori infection, respectively. In multivariable analysis adjusted for age, body mass index, smoking status, alcohol intake, family history of colorectal cancer, and baseline adenoma characteristics, the hazard ratio [95% confidence interval (CI)] for metachronous AN was 1.74 (1.11-2.73) in participants with H. pylori seropositivity, compared with those without H. pylori seropositivity. The association was consistent with H. pylori infection status on the basis of histology (adjusted hazard ratio, 3.51; 95% CI, 1.64-7.51). In the subgroup analysis, the positive association was observed in both no-adenoma and adenoma removal subgroups.

CONCLUSIONS

In a cohort study, H. pylori infection was associated with an increased risk of AN development. This association was consistent in both the serological and histologic assessment of H. pylori infection. Prospective studies are necessary to determine whether H. pylori eradication can reduce the risk of colorectal neoplasia.

Prevalence of Helicobacter pylori among Sudanese patients diagnosed with colon polyps and colon cancer using immunohistochemistry technique

Objectives

Infection with the bacteria Helicobacter pylori has been classified as class one carcinogen associated with increasing susceptibility of gastritis and gastric carcinoma. This study is aiming at investigating the prevalence of H. pylori among colon polyps and colon cancer patients. A descriptive cross-sectional hospital-based study was conducted between February and June 2017. Sixty-nine formalin-fixed paraffin blocks collected from colon polyps and colon cancer patients to detect H. pylori using immunohistochemistry technique.

Results

Of the 69 patients included in the study, 39 (56.5%) males and 30 (43.5%) were females, their age ranged from 21 to 80 years with a mean age of 47.1 ± 19.7. Of the 69 colon polyps and colon cancer patients, 44 (63.8%) were diagnosed as adenocarcinoma, 10 (14.5%) colitis, 15 (21.7%) juvenile polyposis syndrome. The results of immunohistochemistry technique showed the presence of 16 (23.2%) positive patients for H. pylori infection. Of these 16, 13 (81.3%) patients were diagnosed with adenocarcinoma and 3 (18.7%) patients were diagnosed with juvenile polyps. The results of H. pylori detection among the different colon polyps and colon cancer patients were showing a statistically significant association for H. pylori infection and adenocarcinoma, P value 0.028.

Antibody Responses to Helicobacter pylori and Risk of Developing Colorectal Cancer in a European Cohort

BACKGROUND

While Helicobacter pylori (H. pylori) is the major cause of gastric cancer, it has also been suggested to be involved in colorectal cancer development. However, prospective studies addressing H. pylori and colorectal cancer are sparse and inconclusive. We assessed the association of antibody responses to H. pylori proteins with colorectal cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort.

METHODS

We applied H. pylori multiplex serology to measure antibody responses to 13 H. pylori proteins in prediagnostic serum samples from 485 colorectal cancer cases and 485 matched controls nested within the EPIC study. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using multivariable conditional logistic regression to estimate the association of H. pylori overall and protein-specific seropositivity with odds of developing colorectal cancer.

RESULTS

Fifty-one percent of colorectal cancer cases were H. pylori seropositive compared with 44% of controls, resulting in an OR of 1.36 (95% CI, 1.00-1.85). Among the 13 individual H. pylori proteins, the association was driven mostly by seropositivity to Helicobacter cysteine-rich protein C (HcpC; OR: 1.66; 95% CI, 1.19-2.30) and Vacuolating cytotoxin A (VacA) (OR: 1.34; 95% CI, 0.99-1.82), the latter being nonstatistically significant only in the fully adjusted model.

CONCLUSIONS

In this prospective multicenter European study, antibody responses to H. pylori proteins, specifically HcpC and VacA, were associated with an increased risk of developing colorectal cancer.

IMPACT

Biological mechanisms for a potential causal role of H. pylori in colorectal carcinogenesis need to be elucidated, and subsequently whether H. pylori eradication may decrease colorectal cancer incidence.

Helicobacter pylori infection coexisting with intestinal metaplasia is not associated with colorectal neoplasms

Introduction

Colorectal cancer is one of the most common cancers and is a major cause of morbidity and mortality in the world and our country. Studies have indicated that there might be a relationship between Helicobacter pylori (Hp) and colorectal neoplasia (CN), although others have not found any relationship.

Aim

To determine whether there is a potential relationship between Hp and CN in our patients.

Material and methods

A total of 314 patients, aged 16–86 years, who underwent gastroscopy and colonoscopy at our department between 2015 and 2017 were evaluated retrospectively. The age, gender, endoscopy results, presence of Hp, complete blood count (CBC), vitamin B₁₂, folic acid, C-reactive protein (CRP), and sedimentation levels of the patients were examined.

Results

CBC, ferritin, vitamin B₁₂, and CRP measurements did not show statistical significance in terms of the presence of Hp (p > 0.05). Folate values of Hp-positive patients were significantly lower than Hp-negative patients (p = 0.007; p < 0.01). No significant relationship was detected between Hp and colon cancer (p > 0.05). Adenomatous polyps were not related to Hp (p > 0.05). Correlation between intestinal metaplasia (IM) and adenomatous polyps was insignificant. There was no statistically significant difference between colon and gastric pathology results.

Conclusions

In our study, no significant relationship was noted between Hp and CN. A few studies have been conducted in our country, and our results are consistent with some of these studies while it is contradictory to others. Large populational multicentre studies are needed in order to identify the relationship between Hp and CN.

Microbiome and colorectal cancer: Roles in carcinogenesis and clinical potential

The gastrointestinal tract harbors most of the microbiota associated with humans. In recent years, there has been a surge of interest in assessing the relationships between the gut microbiota and several gut alterations, including colorectal cancer. Changes in the gut microbiota in patients suffering colorectal cancer suggest a possible role of host-microbe interactions in the origin and development of this malignancy and, at the same time, open the door for novel ways of preventing, diagnosing, or treating this disease. In this review we survey current knowledge on the healthy microbiome of the gut and how it is altered in colorectal cancer and other related disease conditions. In describing past studies we will critically assess technical limitations of different approaches and point to existing challenges in microbiome research. We will have a special focus on host-microbiome interaction mechanisms that may be important to explain how dysbiosis can lead to chronic inflammation and drive processes that influence carcinogenesis and tumor progression in colon cancer. Finally, we will discuss the potential of recent developments of novel microbiota-based therapeutics and diagnostic tools for colorectal cancer.

Fusobacterium and Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer worldwide and its pathogenesis has been extensively explored over the past decades. Recently, microorganisms in the gastrointestinal tract have emerged as potential etiological agents. In particular, a direct proportional association between Fusobacterium and CRC has been described. Since then, the functional impact of Fusobacterium in CRC development has been studied using various mouse models. Although some epidemiologic studies did not establish an obvious relationship between Fusobacterium and CRC, numerous pathogenic mechanisms leading to the disease have been described. For instance, Fusobacterium can activate the E-cadherin/β-catenin signaling pathway and is associated with particular epigenetic phenotype, such as microsatellite instability (MSI) and hypermethylation, via its strong adhesive and invasive abilities resulting in malignant transformation of epithelial cells. Also, Fusobacterium could alter the tumor microenvironment (TME) significantly by myeloid-derived suppressor cells (MDSCs), tumor associated macrophages (TAMs), and tumor associated neutrophils (TANs) recruitment and local immune suppression. Herein, we provide an in-depth review of the relationship between Fusobacterium and colorectal cancer. In light of the emergence of microbiome-based therapeutics, potential therapies and preventive strategies for colorectal cancer related to Fusobacterium are also discussed.

Review: Diagnostic accuracy of PCR-based detection tests for Helicobacter Pylori in stool samples

BACKGROUND

Although different methods have been established to detect Helicobacter pylori (H. pylori) infection, identifying infected patients is an ongoing challenge. The aim of this meta-analysis was to provide pooled diagnostic accuracy measures for stool PCR test in the diagnosis of H. pylori infection.

METHODS

In this study, a systematic review and meta-analysis were carried out on various sources, including MEDLINE, Web of Sciences, and the Cochrane Library from April 1, 1999, to May 1, 2016. This meta-analysis adheres to the guidelines provided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses report (PRISMA Statement). The clinical value of DNA stool PCR test was based on the pooled false positive, false negative, true positive, and true negative of different genes.

RESULTS

Twenty-six of 328 studies identified met the eligibility criteria. Stool PCR test had a performance of 71% (95% CI: 68-73) sensitivity, 96% (95% CI: 94-97) specificity, and 65.6 (95% CI: 30.2-142.5) diagnostic odds ratio (DOR) in diagnosis of H. pylori. The DOR of genes which showed the highest performance of stool PCR tests was as follows: 23S rRNA 152.5 (95% CI: 55.5-418.9), 16S rRNA 67.9 (95%CI: 6.4-714.3), and glmM 68.1 (95%CI: 20.1-231.7).

CONCLUSIONS

The sensitivity and specificity of stool PCR test are relatively in the same spectrum of other diagnostic methods for the detection of H. pylori infection. In descending order of significance, the most diagnostic candidate genes using PCR detection were 23S rRNA, 16S rRNA, and glmM. PCR for 23S rRNA gene which has the highest performance could be applicable to detect H. pylori infection.

Helicobacter pylori infection is an independent risk factor of early and advanced colorectal neoplasm

BACKGROUND

The role of Helicobacter pylori (H. pylori) in the development of colorectal neoplasm remains controversial. We examined the association between H. pylori infection and colorectal neoplasm in a large sample of healthy participants who underwent screening colonoscopy.

METHODS

A cross-sectional study of 8916 men, who participated in a regular health-screening examination that included an H. pylori-specific immunoglobulin G antibody test and colonoscopy, was conducted to evaluate the association between H. pylori and colorectal neoplasm.

RESULTS

Multivariable analyses adjusted for age, body mass index, smoking status, alcohol intake, regular exercise, regular aspirin use, and family history of colorectal cancer showed that the odds ratio (OR) (95% confidence interval [CI]) for any adenoma and advanced neoplasm was 1.32 (1.07-1.61) and 1.90 (1.05-3.56) in participants with H. pylori infection and without H. pylori infection, respectively. The association persisted after further adjustment for inflammatory markers or metabolic variables including fasting blood glucose, triglycerides, high-density lipoprotein-cholesterol, and low-density lipoprotein-cholesterol. Regarding the location, a positive association was confined to cases with proximal adenomas and was observed similarly in all the evaluated subgroups.

CONCLUSIONS

In a large-scale study, carefully controlled for confounding factors, involving asymptomatic participants without a history of colonoscopy, H. pylori infection was significantly associated with the risk of any colorectal adenoma and advanced colorectal neoplasm. Prospective studies are necessary to determine whether H. pylori eradication can reduce this risk.

Microbiome and colorectal cancer: Unraveling host-microbiota interactions in colitis-associated colorectal cancer development

Dysbiosis of gut microbiota occurs in many human chronic immune-mediated diseases, such as inflammatory bowel disease (IBD) and colitis-associated colorectal cancer (CAC). Reciprocally, uncontrolled immune responses, that may or may not be induced by dysbiosis, are central to the development of IBD and CAC. There has been a surge of interest in investigating the relationship between microbiota, inflammation and CAC. In this review, we discuss recent findings related to gut microbiota and chronic immune-mediated diseases, such as IBD and CAC. Moreover, the molecular mechanisms underlying the roles of chronic inflammation in CAC are examined. Finally, we discuss the development of novel microbiota-based therapeutics for IBD and colorectal cancer.

Association of colorectal cancer with pathogenic Escherichia coli: Focus on mechanisms using optical imaging

AIM: To investigate the molecular or cellular mechanisms related to the infection of epithelial colonic mucosa by pks-positive Escherichia coli (E. coli) using optical imaging.

METHODS: We choose to evaluate the tumor metabolic activity using a fluorodeoxyglucose analogue as 2-deoxyglucosone fluorescent probes and to correlate it with tumoral volume (mm³). Inflammation measuring myeloperoxidase (MPO) activity and reactive oxygen species production was monitored by a bioluminescent (BLI) inflammation probe and related to histological examination and MPO levels by enzyme-linked immunosorbent assay (ELISA) on tumor specimens. The detection and quantitation of these two signals were validated on a xenograft model of human colon adenocarcinoma epithelial cells (HCT116) in nude mice infected with a pks-positive E. coli. The inflammatory BLI signal was validated intra-digestively in the colitis-CEABAC10 DSS models, which mimicked Crohn’s disease.

RESULTS: Using a 2-deoxyglucosone fluorescent probe, we observed a high and specific HCT116 tumor uptake in correlation with tumoral volume (P = 0.0036). Using the inflammation probe targeting MPO, we detected a rapid systemic elimination and a significant increase of the BLI signal in the pks-positive E. coli-infected HCT116 xenograft group (P < 0.005). ELISA confirmed that MPO levels were significantly higher (1556 ± 313.6 vs 234.6 ± 121.6 ng/mL P = 0.001) in xenografts infected with the pathogenic E. coli strain. Moreover, histological examination of tumor samples confirmed massive infiltration of pks-positive E. coli-infected HCT116 tumors by inflammatory cells compared to the uninfected group. These data showed that infection with the pathogenic E. coli strain enhanced inflammation and ROS production in tumors before tumor growth. Moreover, we demonstrated that the intra-digestive monitoring of inflammation is feasible in a reference colitis murine model (CEABAC10/DSS).

CONCLUSION: Using BLI and fluorescence optical imaging, we provided tools to better understand host-pathogen interactions at the early stage of disease, such as inflammatory bowel disease and colorectal cancer.

Helicobacter pylori and colorectal neoplasia: Is there a causal link?

Ever since Helicobacter pylori (H. pylori) was recognized as an infectious cause of gastric cancer, there has been increasing interest in examining its potential role in colorectal carcinogenesis. Data from case-control and cross-sectional studies, mostly relying on hospital-based samples, and several meta-analyses have shown a positive statistical relationship between H. pylori infection and colorectal neoplasia. However, the possibility exists that the results have been influenced by bias, including the improper selection of patients and disparities with respect to potential confounders. While the evidence falls short of a definitive causal link, it appears that infection with H. pylori/H. pylori-related gastritis is associated with an increased, although modest, risk of colorectal adenoma and cancer. The pathogenic mechanisms responsible for this association remain uncertain. H. pylori has been detected in colorectal malignant tissues; however, the possibility that H. pylori is a direct activator of colonic carcinogenesis remains purely hypothetical. On the other hand, experimental data have indicated a series of potential oncogenic interactions between these bacteria and colorectal mucosa, including induction and perpetuation of inflammatory responses, alteration of gut microflora and release of toxins and/or hormonal mediators, such as gastrin, which may contribute to tumor formation.

Gut microbiota imbalance and colorectal cancer

The gut microbiota acts as a real organ. The symbiotic interactions between resident micro-organisms and the digestive tract highly contribute to maintain the gut homeostasis. However, alterations to the microbiome caused by environmental changes (e.g., infection, diet and/or lifestyle) can disturb this symbiotic relationship and promote disease, such as inflammatory bowel diseases and cancer. Colorectal cancer is a complex association of tumoral cells, non-neoplastic cells and a large amount of micro-organisms, and the involvement of the microbiota in colorectal carcinogenesis is becoming increasingly clear. Indeed, many changes in the bacterial composition of the gut microbiota have been reported in colorectal cancer, suggesting a major role of dysbiosis in colorectal carcinogenesis. Some bacterial species have been identified and suspected to play a role in colorectal carcinogenesis, such as Streptococcus bovis, Helicobacter pylori, Bacteroides fragilis, Enterococcus faecalis, Clostridium septicum, Fusobacterium spp. and Escherichia coli. The potential pro-carcinogenic effects of these bacteria are now better understood. In this review, we discuss the possible links between the bacterial microbiota and colorectal carcinogenesis, focusing on dysbiosis and the potential pro-carcinogenic properties of bacteria, such as genotoxicity and other virulence factors, inflammation, host defenses modulation, bacterial-derived metabolism, oxidative stress and anti-oxidative defenses modulation. We lastly describe how bacterial microbiota modifications could represent novel prognosis markers and/or targets for innovative therapeutic strategies.

The association of H. pylori and colorectal adenoma: does it exist in the US Hispanic population?

BACKGROUND

Although data on the association between colorectal adenomas and Helicobacter pylori (H. pylori) exists in White and Black patients, there is no data on this association in a US Hispanic population. Our aim was to study the association of adenoma detection and biopsy proven H. pylori infection in a cohort of US Hispanics.

METHODS

Data were collected from Nassau University Medical Center, a 530-bed tertiary care teaching hospital in East Meadow, New York. Patients who underwent both an esophagogastroduodenoscopy (EGD) and colonoscopy from July 2009 to March 2011 were pulled from an electronic database. A total of 1,737 patients completed colonoscopies during this time with 95 excluded: 17 inflammatory bowel disease, 12 malignancy, 22 prior history of colorectal adenoma, and 44 incomplete. Among the colonoscopies, 799 patients had EGD's performed prior to colonoscopies that were eligible for our study.

RESULTS

H. pylori prevalence was highest in Hispanics 40.9%, followed by Blacks 29.1% (OR 0.59, 95% CI: 0.42-0.84), then Whites 7.9% (OR 0.12, 95% CI: 0.06-0.24). The adenoma detection rate was significantly higher in Whites 23.2% and Blacks 21.8% compared to Hispanics 14.5%, P=0.0002 respectively. Smoking and alcohol were lower in the H. pylori group, 18.6% (n=44) vs. 26.1% (n=147) for smoking (P=0.02) and 14.4% (n=34) vs. 19% (n=107) for alcohol (P=0.12), respectively. There was no evidence in the Hispanics for an association between adenoma detection and H. pylori infection. Furthermore size, location, and multiple polyps did not differ between the two groups.

CONCLUSIONS

While data has shown an association between H. pylori and colorectal adenomas, we did not find this in our Hispanic population. With the growing population of Hispanics in the U.S, large scale studies are needed to conclusively characterize the role of H. pylori infection in colorectal adenoma and adenocarcinoma in this group of patients.

Gastric Helicobacter pylori infection associates with an increased risk of colorectal polyps in African Americans

Background

Gastric Helicobacter pylori (H. pylori) infection and colorectal polyps are more prevalent in African Americans than in the general population. We aimed to investigate whether gastric H. pylori infection is associated with colorectal polyps in African Americans.

Methods

Medical records of African Americans, 40 years and older (n = 1256) who underwent bidirectional gastrointestinal endoscopy on the same day were reviewed. H. pylori status was assessed by immunohistochemistry on gastric specimens. Colorectal polyps were confirmed by histological examination of colorectal biopsies. A subset of serum samples from healthy and polyp-bearing patients (n = 163) were analyzed by ELISA for anti-H. pylori and anti-CagA antibodies. The crude and adjusted effect of H. pylori on the risk of colorectal adenoma and polyp were computed by logistic regression models.

Results

The prevalence of colorectal polyps and adenomas were 456 (36%) and 300 (24%) respectively. Colorectal polyps were more prevalent in gastric H. pylori infected than non-infected subjects [43% vs. 34%; Odds Ratio (OR) (95% CI): 1.5 (1.2-1.9), P = 0.001]. Patients with H. pylori-associated chronic active gastritis were at high risk to have adenomas [Unadjusted OR (95% CI): 1.3 (1.0-1.8); P = 0.04]. There was no difference in histopathology, size, or location of polyps with respect to H. pylori status. Gastric H. pylori infection, age, male gender and high risk clinical presentations were independent risk factors for colorectal polyps. Serological testing also revealed a higher prevalence of H. pylori and its toxin Cag-A in polyp patients vs. non polyp patients’ sera, although in a non-statistically significant manner.

Conclusions

This study showed that current gastric H. pylori infection is associated with an increased risk of colorectal polyps in African Americans. Patients with H. pylori induced gastritis may benefit from early screening colonoscopy as a preventative measure for colorectal cancer.

Association between Helicobacter pylori infection and the risk of colorectal neoplasia: a systematic review and meta-analysis

AIM

The existing evidence on the relationship between Helicobacter pylori infection and the risk of colorectal neoplasia is inconsistent. We conducted a systematic review with a meta-analysis to explore this relationship and to determine whether the relationship varies according to the study characteristics.

METHOD

We searched the PubMed database and the reference lists of pertinent articles published up to July 2012. Summary odds ratios (ORs) with their 95% confidence intervals (CIs) were estimated using a random-effects model.

RESULTS

Twenty-seven studies including 3792 cases of colorectal adenoma (CRA) and 3488 cases of colorectal cancer (CRC) were identified. Overall, H. pylori infection was associated with an increased risk of CRA (OR = 1.66, 95% CI 1.39-1.97, I(2)  = 54.3%) and CRC (OR = 1.39, 95% CI 1.18-1.64, I(2)  = 35.8%), although there was significant heterogeneity among the studies. Subgroup analysis revealed that the positive correlation did not differ by sex, geographic variation or subsite of neoplasia, but might vary by the method of detection of H. pylori. The study was underpowered to determine the risk of colorectal neoplasia associated with cytotoxin-associated gene A-positive H. pylori.

CONCLUSION

This meta-analysis demonstrates a positive association between H. pylori infection and the risk of colorectal neoplasia.

454-pyrosequencing analysis of normal gastric mucosal microbiota

AIM: To characterize the normal gastric microbiota.

METHODS: Genomic DNA was extracted from antral biopsies obtained from two patients who had histologically normal gastric mucosa. The 16S rRNA gene was amplified using PCR. The barcoded 454-pyrosequencing method was used to analyze the amplified products. To investigate the community structure, diversity and abundance of gastric microbiota, sequence analysis was performed using bioinformatic methods including OTU hierarchical clustering and alpha diversity analysis.

RESULTS: High-throughout sequencing of the gastric microbiota from patients A and B obtained 20565 and 17487 sequences, respectively. The coverage was greater than 0.98. Gastric microbiota was composed of 638 and 667 OTUs, respectively. Alpha diversity analysis revealed that Chao and Shannon indices of gastric microbiota were slightly lower than those of fecal microbiota. For patient A, the gastric microbiota was composed of 58 bacterial genera belonging to 14 phyla. Proteobacteria, Actinomycetes, Firmicutes and Bacteroides were dominant in the gastric microbiota from patient A. The gastric microbiota from patient B had a similar bacterial composition, consisting of 64 bacterial genera belonging to 19 phyla. Serratia was the predominant genus in both patients.

CONCLUSION: Normal gastric microbiota shows a high diversity. Proteobacteria is the most abundant phylum, while Serratia is the predominant genus.

Pathogen-driven gastrointestinal cancers: Time for a change in treatment paradigm?

The regulation of cancerous tumor development is converged upon by multiple pathways and factors. Besides environmental factors, gastrointestinal (GI) tract cancer can be caused by chronic inflammation, which is generally induced by bacteria, viruses, and parasites. The role of these inducers in cancer development, cell differentiation and transformation, cell cycle deregulation, and in the expression of tumor-associated genes cannot be ignored. Although Helicobacter pylori activates many oncogenic pathways, particularly those in gastric and colorectal cancers, the role of viruses in tumor development is also significant. Viruses possess significant oncogenic potential to interfere with normal cell cycle control and genome stability, stimulating the growth of deregulated cells. An increasing amount of recent data also implies the association of GI cancers with bacterial colonization and viruses. This review focuses on host-cell interactions that facilitate primary mechanisms of tumorigenesis and provides new insights into novel GI cancer treatments.

Helicobacter pylori infection increases the risk of colorectal adenomas: cross-sectional study and meta-analysis

BACKGROUND

The studies concerning the association between Helicobacter pylori status and colorectal adenoma, premalignant lesions of colorectal cancers, are not consistent.

METHODS

This cross-sectional study investigated the association of colorectal adenoma with H. pylori infection in a consecutive series of 2,195 asymptomatic average-risk subjects who underwent screening colonoscopy and H. pylori testing. Multivariate analyses were adjusted for potential relevant confounders, including age, sex, smoking, alcohol consumption, family history of colorectal cancer, and regular use of aspirin. Furthermore, we performed a systematic literature review and meta-analysis of available studies, including the current study, to clarify whether H. pylori infection is associated with an increased risk of colorectal adenoma.

RESULTS

Among 2,195 eligible subjects, 1,253 subjects were H. pylori seropositive and 942 subjects were seronegative. In the H. pylori (+) group, the prevalence of colorectal adenoma and advanced adenoma was significantly higher than in the H. pylori (-) group (25.3 vs. 20.1 %, p = 0.004 and 6.1 vs. 2.9 %, p < 0.001, respectively). In our multivariate analysis, H. pylori seropositivity was an independent risk factor for overall colorectal adenoma (OR = 1.36, 95 % CI = 1.10-1.68) and advanced adenoma (OR = 2.21, 95 % CI = 1.41-3.48). The positive association was confined in cases with any proximal adenoma. In the meta-analysis, which included ten studies and 15,863 patients, the pooled OR for colorectal adenoma related to H. pylori infection was 1.58 (95 % CI = 1.32-1.88).

CONCLUSION

Our results from this cross-sectional study and current studies included in our meta-analysis indicated that H. pylori infection was associated with a modest increase in the risk for colorectal adenoma.

The presence of Helicobacter pylori in colorectal polyps detected by immunohistochemical methods in children

AIM

Polyps are a common cause of hematochezia in children, but the pathogenesis of polyps is unclear. The aim of this study was to investigate the relationship between Helicobacter pylori (HP) infection and colorectal polyps in children.

METHODS

Thirty-five patients who had undergone polypectomy after the detection of polyps served as the case group. Twenty-seven patients with gastrointestinal symptoms and normal colonoscopy served as the control group. Hematoxylin and eosin (HE) stains obtained from paraffin blocks were evaluated and classified according to histopathologic type and degree of dysplasia. The other sections were used to detect HP organisms for immunohistochemistry (IHC). The seroprevalence of HP antibodies in children with colorectal polyps was detected by protein chip technology. HP infection was diagnosed if the serum urease antibody was positive.

RESULTS

The HP-positive rate in children with colorectal polyps was 57.1% (20/35), which was higher than the rate of 22.2% (6/27) for colonic mucosa in the control group (P < 0.01). The differences in the presence and absence of HP infection between patients with juvenile polyps and juvenile polyposis syndrome were not statistically significant. Age, gender, and the number, size, and locations of the colonic polyps were not significantly different between the patients with HP-positive and HP-negative polyps. The HP-antibody-positive rate was 65.0% (13/20) in the patients with HP-infection-positive colorectal polyps, which was higher than the rate of 26.7% (4/15) for the patients with HP-infection-negative colorectal polyps (P < 0.05).

CONCLUSION

Our findings suggest a positive association between HP infection and colorectal polyps in children in this study, indicating that HP infection is a risk factor for colorectal polyps in children.

PCR in Helicobacter spp. diagnostic in extragastric malignancies of digestive system

Recognition of Helicobacter pylori as an important factor in genesis of gastric adenocarcinoma lead to a large number of studies concerning potential role of Helicobacter spp. in the development of extragastric digestive malignancies. The serological studies indicated possible localizations in the digestive system being from interest in enlightening Helicobacter spp. carcinogenic potential. The PCR obtruded itself as a gold standard in proving existence of actual correlation. In this review, the authors have examined studies conducted in the last 10 years examining Helicobacter spp. correlation with extragastric digestive carcinogenesis. Studies have been observed in four groups referring to hepatic carcinoma, bile duct cancer, pancreatic cancer, and colon cancer. The results of these researches have shown that there is a strong correlation between Helicobacter spp. colonization and primary liver tumors as well as bile duct tumors, whereas conclusions made by authors examining pancreatic cancer are contradictory and demands further investigation. No correlation between Helicobacter spp. and colon cancer have been proven. The PCR subtype most widely used in studies included in this review was nested PCR, whereas genes targeted most frequently for amplification are 16S rDNA of Helicobacter spp. and UreA gene or cagA gene of H. pylori. During the last 10 years PCR has proven itself as a sovereign method for Helicobacter spp. diagnostic in extragastric organs in the digestive system. Knowledge and experiences obtained in this domain could be encouraging for researchers in analogous fields of interest.

Infectious causes of colorectal cancer

Colorectal cancer is a major cause of cancer-related morbidity and mortality in the United States and many other regions of the world. Our understanding of the pathogenesis of colorectal cancer, from the precursor adenomatous polyp to adenocarcinoma, has evolved rapidly. Colorectal carcinogenesis is a sequential process characterized by the accumulation of multiple genetic and molecular alterations in colonic epithelial cells. However, the development of colorectal cancer involves more then just a genetic predisposition. External or environmental factors presumably play a significant role, and inflammatory bowel diseases, obesity, alcohol consumption, and a diet high in fat and low in fiber have all been implicated as risk factors for the development of either colonic adenomas or carcinomas. We are becoming increasingly aware of microbes as causes of malignancies. This article reviews the various microbes that have been associated with the development of colorectal carcinomas.

Helicobacter pylori infection concomitant with metabolic syndrome further increase risk of colorectal adenomas

AIM

To investigate the association of colorectal adenomas with both Helicobacter pylori (H. pylori) infection and metabolic syndrome.

METHODS

Using a cross-sectional hospital-based study, we analyzed physical examination data from 9311 healthy subjects with overnight physical examinations performed between January 2004 and December 2006. Examined data included gender, age, life style, anthropometric measurements, blood pressure, biochemical and hematological studies, H. pylori infection detected by esophagogastroduodenoscopy and biopsy urease tests, and colorectal adenomas detected with a complete total colonoscopy.

RESULTS

The prevalence values for H. pylori infection, metabolic syndrome, and colorectal adenoma were 39.2%, 18.7%, and 20.7%, respectively. Colorectal adenoma risk factors included male gender [odd ratio (OR): 2.005, 95% confidence interval (CI): 1.740-2.310, P < 0.001], advanced age (OR: 1.046, 95% CI: 1.040-1.052, P < 0.001), smoking (OR: 1.377, 95% CI: 1.146-1.654, P = 0.001), increased body fat (OR: 1.016, 95% CI: 1.007-1.026, P = 0.001), higher white blood cell count (OR: 1.038, 95% CI: 1.005-1.073, P = 0.025), H. pylori infection (OR: 1.366, 95% CI: 1.230-1.517, P < 0.001), and metabolic syndrome (OR: 1.408, 95% CI: 1.231-1.610, P < 0.001). In addition, concomitant H. pylori infection with metabolic syndrome further increased the probability of colorectal adenomas.

CONCLUSION

Our study revealed H. pylori infection with concomitant metabolic syndrome might further increase the risk of colorectal adenomas.

Seroprevalence of Helicobacter pylori in patients with colon adenomas in a brazilian university hospital

CONTEXT: The association between Helicobacter pylori infection and colon neoplasia has been the subject of recent investigations which have produced controversial results. OBJECTIVE: To evaluate the prevalence of H. pylori infection in patients with colonic adenomas and also in patients whose colonoscopy exams were normal. METHODS: After colonoscopy, the individuals were distributed into two groups: patients with colon adenomas (cases) and patients whose colons were normal (controls). The groups were similar regarding age and gender. The individuals of both groups were subjected to a dosage of IgG antibody against H. pylori. The dosage was applied according to the solid phase, chemiluminescent immunometric assay. The chi-square test was used to analyze the data. RESULTS: There were 30 men and 64 women in each group (94 cases and 94 controls). The mean age of the cases was 59.79 ± 12.25 years and that of the controls was 58.98 ± 11.55 years. The H. pylori serology was positive for 66 (70.21%) of the cases and for 51 (54.25%) of the controls. There was a significant difference (P = 0.024). The odds ratio was 1.98 (CI 95%, 0.82-3.15). The prevalence of H. pylori in cases and controls according to gender, histological type and location of the colon lesions showed a significant difference only among women (P = 0.03), among patients with tubular adenomas (P = 0.03), and in those with distal adenomas (P = 0.038). CONCLUSION: There is a positive association between H. pylori infection and colonic adenomas. This association is more evident in women, especially for tubular adenomas and distal colonic location.

Infectious agents and colorectal cancer: a review of Helicobacter pylori, Streptococcus bovis, JC virus, and human papillomavirus

Based on the high volume of bacteria and viruses that the intestine is exposed to and the importance of infectious agents in some gastrointestinal and anogenital cancers, it is not surprising the many studies have evaluated the association between colorectal cancer and infectious agents. This review highlights investigations of four agents in relation to colorectal cancer. Helicobacter pylori, Streptococcus bovis, JC virus, and human papillomavirus have all been evaluated as possible etiologic agents for colorectal cancer. For each of these agents, a review of possible mechanisms for carcinogenesis and epidemiologic evidence is discussed, and future directions for research are proposed.

Immunohistochemical testing for Helicobacter Pylori existence in neoplasms of the colon

Background

Helicobacter pylori is a common pathogen, and its prevalence varies with socioeconomic conditions (10–80%). It has recently been recognized as a class I carcinogen in relation to gastric cancer. The aim of this study was to investigate the presence of Helicobacter pylori in neoplasms of the colon by immunohistochemical methods.

Methods

The polypectomy materials of 51 patients (19 male and 32 female) who had undergone colonoscopic polypectomy were retrieved for retrospective examination. The endoscopic size and colonic localization of the polyps were recorded. Hematoxylin and eosin stains were evaluated according to histological type and grade of dysplasia. Biopsy stains were immunohistochemically treated with Helicobacter pylori antibodies by the streptavidine-biotin immunoperoxidase technique. Helicobacter pylori staining in the gastric mucosa was used as the control for the immunohistochemical method. Specimens were classified according to the presence of Helicobacter pylori under an optical microscope, and Helicobacter pylori positive specimens were stratified according to the respective staining pattern.

Results

Mean age was 61.88 ± 10.62 (40–82) years. Polyp sizes were 1.45 ± 0.92 (1–4) cm; and 25.5% of polyps were localized in the right colon, 68.6% in the left colon and 5.9% in the transverse colon. Presence of Helicobacter pylori was not correlated with localization (p > 0.05) or size of the polyps (p > 0.05).

Eleven (21.6%) of all specimens included in the study were Helicobacter pylori positive by immunohistochemical methods. Of the Helicobacter pylori positive specimens, the staining pattern was diffuse: Equivocal in 90.9%, nonspecific with a finely granular type concentrated on the luminal surface in 90.9%, dot-like granular in 54.5%, and spiral in 9.1%. Of the tubular polyps, 17.9% were H. pylori positive, and the staining pattern was equivocal in 100%, luminal in 85.7%, and dot-like granular in 57.1%. Of the villous polyps, 60% were H. pylori positive, and the staining pattern was inconclusive in 66.7%, luminal in 100%, dot-like granular in 33.3%, and spiral in 33.3%. Of the cancerous cases, 25% were H. pylori positive and showed an equivocal, luminal, and dot-like granular staining pattern. No significant correlation was determined between histologic types and prevalence of H. pylori (p > 0.05).

Conclusion

The presence of H. pylori in colon polyps did not yield any correlation with polyp size, colonic localization or histopathologic type. The higher rate of H. pylori positivity in villous polyps does not present a causal relationship. We were able to determine H. pylori existence in colon polyps by immunohistochemical methods, albeit with no statistical significance.

Use of single-strand conformation polymorphism of amplified 16S rDNA for grouping of bacteria isolated from foods

The grouping method for isolated strains from foods using single-strand conformation polymorphism (SSCP) after PCR amplification of a portion of 16S rDNA was developed. This method was able to group the strains from various food samples based on 16S rDNA sequence. As 97.8% of the isolated strains from various foods were grouped correctly, use of the PCR-SSCP method enables the prompt and labor-saving analysis of microbial population of food-derived bacterial strains. Advantages in speed and accuracy of bacterial population identification by the PCR-SSCP method have practical application for food suppliers and testing laboratories.

Helicobacter pylori in colorectal neoplasms: is there an aetiological relationship?

BACKGROUND

This pilot study was carried out to determine whether Helicobacter pylori can be detected in normal colon or in association with colorectal neoplasia.

METHODS

Paraffin processed colonic tissue blocks of normal colonic mucosa (n = 60), and patients diagnosed as adenoma (n = 60), and adenocarcinoma (n = 60) were retrieved from our archive; the adenoma group included tubular (n = 20), tubulovillous (n = 20) and villous adenomas (n = 20). 4 mum sections were stained by immunohistochemical methods using anti-Helicobacter pylori antibodies (polyclonal NCL-HPp and monoclonal NCL-C-jejuni).

RESULTS

Significant numbers of Helicobacter pylori were identified in tubular adenomas (OR = 11.13; 95%CI = 1.62-76.70), tubulovillous adenomas (OR = 10.45; 95%CI = 1.52-71.52) and adenocarcinomas (OR = 8.13; 95%CI = 1.40-46.99) compared to controls: there was no association in numbers of Helicobacter pylori and villous adenomas (OR = 2.95; 95%CI = 0.29-9.96).

CONCLUSION

We conclude that although, in this pilot study, there appears to be an association in the prevalence of Helicobacter pylori with some, but not all, colorectal neoplasms, we can not infer causality from these results. These findings need to be further substantiated with a prospective study and the use of molecular biological techniques to determine a causal association.