Polymorphisms of inflammatory and metalloproteinase genes, Helicobacter pylori infection and the risk of oesophageal adenocarcinoma

Systematic Review with Meta-analysis: Association of Helicobacter pylori Infection with Esophageal Cancer

Background

Helicobacter pylori is an important carcinogenic factor in gastric cancer. Studies have shown that Helicobacter pylori infection is inversely associated with certain diseases such as esophageal cancer and whose infection appears to have a “protective effect.” At present, the relationship between Helicobacter pylori infection and esophageal cancer remains controversial. This study was designed to investigate the relationship between Helicobacter pylori infection and the risk of esophageal cancer in different regions and ethnicities.

Methods

Systematic search of the articles on the relationship between Helicobacter pylori infection and esophageal cancer from the database with the duration time up to December 2018. This systematic review was performed under the MOOSE guidelines.

Results

This meta-analysis included 35 studies with 345,886 patients enrolled. There was no significant correlation between Helicobacter pylori infection and esophageal squamous cell carcinoma in the general population (OR: 0.84; 95% CI: 0.64-1.09/OR: 0.74; 95% CI: 0.54-0.97). However, a significant correlation was found in the Middle East (OR: 0.34; 95% CI: 0.22-0.52/95% CI: 0.26-0.44). There was no significant difference in the prevalence of Helicobacter pylori between the case group and the control group in esophageal adenocarcinoma (8.87% vs. 9.67%). The pooled OR was 0.55 (95% CI: 0.43-0.70) or 0.23 (95% CI: 0.15-0.36). When grouped by match or not, the pooled OR of the nonmatching group and the matching group was 0.48/0.21 (95% CI: 0.36-0.65/95% CI: 0.13-0.36) and 0.73/0.71 (95% CI: 0.57-0.92/95% CI: 0.60-0.84), respectively.

Conclusion

In the general populations, no significant association was found between Helicobacter pylori infection and the risk of esophageal squamous cell carcinoma. However, lower risk was found in the Middle East. Helicobacter pylori infection may reduce the risk of esophageal adenocarcinoma, but such “protection effect” may be overestimated.

Helicobacter pylori infection and esophageal adenocarcinoma: a review and a personal view

Esophageal adenocarcinoma (EAC) is etiologically associated with gastroesophageal reflux disease (GERD). There is evidence to support the sequence GERD, Barrett's esophagus (BE), dysplasia, and finally EAC, with Helicobacter pylori (H. pylori) being implicated in each step to EAC. On the other side of this relation stands the hypothesis of the protective role of H. pylori against EAC. Based on this controversy, our aim was to review the literature, specifically original clinical studies and meta-analyses linking H. pylori infection with EAC, but also to provide our personal and others' relative views on this topic. From a total of 827 articles retrieved, 10 original clinical studies and 6 meta-analyses met the inclusion criteria. Original studies provided inconclusive data on an inverse or a neutral association between H. pylori infection and EAC, whereas meta-analyses of observational studies favor an inverse association. Despite these data, we consider that the positive association between H. pylori infection and GERD or BE, but not EAC, is seemingly a paradox. Likewise, the oncogenic effect of H. pylori infection on gastric and colon cancer, but not on EAC, also seems to be a paradox. In this regard, well-designed prospective cohort studies with a powered sample size are required, in which potential confounders should be taken into consideration since their design.

Neutrophil to Lymphocyte Ratio as Prognostic Indicator for Patients with Esophageal Squamous Cell Cancer

Background

This study aimed to evaluate the correlation between neutrophil to lymphocyte ratio (NLR) with overall survival (OS) of esophageal squamous cell carcinoma (ESCC) patients.

Method

Records of patients with diagnosed ESCC were reviewed. Leukocyte counts and patients' characteristics were extracted from their clinical records to calculate NLR. Correlation between NLR and baseline characteristics with overall survival (OS) was then analyzed using Cox regression. The patients were then separated into higher and lower NLR groups according to median NLR. OS was further compared between the 2 groups.

Results

A total of 1281 patients were included in the study. Cox regression analysis showed a significant correlation of NLR with OS of ESCC patients. The median pretreatment NLR was identified as 2.86. Higher NLR was associated with worse prognosis in terms of OS.

Conclusions

Pretreatment NLR is independently associated with OS of ESCC patients. Therefore, NLR may be used as a predictive indicator for pretreatment evaluation and adjustment of treatment regimen.

Matrix metalloproteinases and gastrointestinal cancers: Impacts of dietary antioxidants

The process of carcinogenesis is tightly regulated by antioxidant enzymes and matrix degrading enzymes, namely, matrix metalloproteinases (MMPs). Degradation of extracellular matrix (ECM) proteins like collagen, proteoglycan, laminin, elastin and fibronectin is considered to be the prerequisite for tumor invasion and metastasis. MMPs can degrade essentially all of the ECM components and, most MMPs also substantially contribute to angiogenesis, differentiation, proliferation and apoptosis. Hence, MMPs are important regulators of tumor growth both at the primary site and in distant metastases; thus the enzymes are considered as important targets for cancer therapy. The implications of MMPs in cancers are no longer mysterious; however, the mechanism of action is yet to be explained. Herein, our major interest is to clarify how MMPs are tied up with gastrointestinal cancers. Gastrointestinal cancer is a variety of cancer types, including the cancers of gastrointestinal tract and organs, i.e., esophagus, stomach, biliary system, pancreas, small intestine, large intestine, rectum and anus. The activity of MMPs is regulated by its endogenous inhibitor tissue inhibitor of metalloproteinase (TIMP) which bind MMPs with a 1:1 stoichiometry. In addition, RECK (reversion including cysteine-rich protein with kazal motifs) is a membrane bound glycoprotein that inhibits MMP-2, -9 and -14. Moreover, α2-macroglobulin mediates the uptake of several MMPs thereby inhibit their activity. Cancerous conditions increase intrinsic reactive oxygen species (ROS) through mitochondrial dysfunction leading to altered protease/anti-protease balance. ROS, an index of oxidative stress is also involved in tumorigenesis by activation of different MAP kinase pathways including MMP induction. Oxidative stress is involved in cancer by changing the activity and expression of regulatory proteins especially MMPs. Epidemiological studies have shown that high intake of fruits that rich in antioxidants is associated with a lower cancer incidence. Evidence indicates that some antioxidants inhibit the growth of malignant cells by inducing apoptosis and inhibiting the activity of MMPs. This review is discussed in six subchapters, as follows.

Association of Helicobacter pylori infection with esophageal adenocarcinoma and squamous cell carcinoma: a meta-analysis

To evaluate the relationship of Helicobacter pylori and cytotoxin-associated gene A (CagA) positive strains with esophageal neoplasm, including esophageal adenocarcinoma (EAC) and esophageal squamous cell carcinoma (ESCC), the authors conducted a meta-analysis using a predefined protocol. PubMed, Web of Science, China biology medical literature database, Wanfang, and China National Knowledge Infrastructure were searched for relevant articles from the first available year to April 8, 2013. The fixed or random effect pooled measure was selected based on heterogeneity among studies, which was evaluated using Q test and the I(2) of Higgins and Thompson. Metaregression was used to explore the sources of between-study heterogeneity. Publication bias was analyzed by Begg's funnel plot and Egger's regression test. The association was assessed by odds ratio (OR) with 95% confidence interval (CI). A total of 28 eligible studies were included in the meta-analysis. There was a significant inverse association between H. pylori infection (pooled OR, 0.57; 95% CI, 0.44-0.73) and EAC; CagA-positive H. pylori strains were less likely to be associated with EAC compared with CagA-negative strains (pooled OR, 0.64; 95% CI, 0.52-0.79). However, there was no statistically significant association between H. pylori/CagA-positive H. pylori strains infection and ESCC, and the pooled ORs were 1.16 (95% CI, 0.83-1.60) and 0.97 (95% CI, 0.79-1.19). But significant associations between CagA-positive H. pylori strains infection and ESCC risk were found in the stratified analysis of the study location (Asian and non-Asian), and the summary ORs were 0.74 (95% CI, 0.57-0.97) and 1.41 (95% CI, 1.02-1.94). H. pylori infection and CagA-positive strains are associated with decreased risk of EAC in the overall population. No significant association was found between H. pylori infection/CagA-positive strains and ESCC. But CagA-positive strains might have a positive association with ESCC in non-Asian population and an inverse association in Asian population.

Helicobacter pylori infection and esophageal cancer risk: an updated meta-analysis

AIM

To clarify the association between Helicobacter pylori (H. pylori) infection and the risk of esophageal carcinoma through a meta-analysis of published data.

METHODS

Studies which reported the association between H. pylori infection and esophageal cancer published up to June 2013 were included. The odds ratios (ORs) and corresponding 95%CIs of H. pylori infection on esophageal cancer with respect to health control groups were evaluated. Data were extracted independently by two investigators and discrepancies were resolved by discussion with a third investigator. The statistical software, STATA (version 12.0), was applied to investigate heterogeneity among individual studies and to summarize the studies. A meta-analysis was performed using a fixed-effect or random-effect method, depending on the absence or presence of significant heterogeneity.

RESULTS

No significant association between H. pylori infection and esophageal squamous cell carcinoma (ESCC) risk was found in the pooled overall population (OR = 0.97, 95%CI: 0.76-1.24). However, significant associations between H. pylori infection and ESCC risk were found in Eastern subjects (OR = 0.66, 95%CI: 0.43-0.89). Similarly, cytotoxin-associated gene-A (CagA) positive strains of infection may decrease the risk of ESCC in Eastern subjects (OR = 0.77, 95%CI: 0.65-0.92), however, these associations were not statistically significant in Western subjects (OR = 1.26, 95%CI: 0.97-1.63). For esophageal adenocarcinoma (EAC) the summary OR for H. pylori infection and CagA positive strains of infection were 0.59 (95%CI: 0.51-0.68) and 0.56 (95%CI: 0.45-0.70), respectively.

CONCLUSION

H. pylori infection is associated with a decreased risk of ESCC in Eastern populations and a decreased risk of EAC in the overall population.

Single-nucleotide polymorphisms of matrix metalloproteinases and their inhibitors in gastrointestinal cancer

Matrix metalloproteinases (MMPs) are implicated in cancer development and progression and are associated with prognosis. Single-nucleotide polymorphisms (SNPs) of MMPs, most frequently located in the promoter region of the genes, have been shown to influence cancer susceptibility and/or progression. SNPs of MMP-1, -2, -3, -7, -8, -9, -12, -13 and -21 and of the tissue inhibitor of metalloproteinases (TIMPs) TIMP-1 and TIMP-2 have been studied in digestive tract tumors. The contribution of these polymorphisms to the cancer risk and prognosis of gastrointestinal tumors are reviewed in this paper.

p53 Arg72Pro, MDM2 T309G and CCND1 G870A polymorphisms are not associated with susceptibility to esophageal adenocarcinoma

p53 Arg72Pro, MDM2 T309G, and CCND1 G870A are functional single-nucleotide polymorphisms (SNPs) in key genes that regulate apoptosis and cell cycle. Variant genotypes of these SNPs have been associated with increased risk and earlier age of onset in some cancers. We investigated the association of these SNPs with susceptibility to esophageal adenocarcinoma in a large, North American case-control study. Three hundred and twelve cases and 454 cancer-free controls recruited in Boston, USA were genotyped for each of the three SNPs, and demographic and clinical data were collected. Genotype frequencies for each of the three SNPs did not deviate from the Hardy-Weinberg equilibrium, and did not differ between cases and controls. Odds ratios (OR), adjusted for clinical risk factors, for the homozygous variant genotypes were 0.99 (95% confidence interval [CI] 0.57-1.72) for p53 Pro/Pro, 0.81 (95% CI 0.52-1.28) for MDM2 G/G, and 0.97 (95% CI 0.64-1.49) for CCND1 A/A. The analysis was adequately powered (80%) to detect ORs of 1.37, 1.35, and 1.34 for each SNP, respectively. In contrast to the results of smaller published studies, no association between p53 Arg72Pro, MDM2 T309G, and CCND1 G870A SNPs and susceptibility to esophageal adenocarcinoma, age of onset, or stage of disease at diagnosis was detected.

Pharmacokinetics and pharmacogenomics in esophageal cancer chemoradiotherapy

Esophageal cancer is one of the most lethal malignancies. Surgical resection of the tumor from the primary site has been the standard treatment, especially for localized squamous cell carcinoma, but considerable clinical efforts during the last decade have resulted in novel courses of treatment. These options include chemoradiotherapy, consisting of a continuous infusion of 5-fluorouracil (5-FU), cisplatin (CDDP), and concurrent radiation. Given the substantial inter- and/or intra-individual variation in clinical outcome, future improvements will likely require the incorporation of a novel anticancer drug, pharmacokinetically guided administration of CDDP or 5-FU, and identification of potential responders by patient genetic profiling prior to treatment. In this review, the latest information on incidence, risk factors, biomarkers, therapeutic strategies, and the pharmacokinetically guided or genotype-guided administration of CDDP and 5-FU is summarized for future individualization of esophageal cancer treatment.

Helicobacter pylori and esophageal cancer risk: a meta-analysis

We conducted this meta-analysis to examine the association between Helicobacter pylori and esophageal adenocarcinoma (EAC) and esophageal squamous cell carcinoma. We searched the PubMed database, the ISI database, and the references of the selected articles. Case-control or nested case-control studies were selected if they used serology or endoscopic methods to detect H. pylori in the stomach and if control subjects were not restricted to upper gastrointestinal tract cancer or peptic ulcer disease patients. A total of 19 studies were used for this analysis. Summary odds ratios (OR) and 95% confidence intervals (95% CI) were calculated using the DerSimonian-Laird method. Q statistics and I(2) statistics were calculated to examine heterogeneity. Subgroup analyses were conducted by CagA status. For EAC, the summary OR (95% CI) was 0.56 (0.46-0.68). There was little heterogeneity among studies (I(2) = 15%). Further analysis showed that colonization with CagA-positive strains was inversely associated with EAC risk (OR, 0.41; 95% CI, 0.28-0.62) but colonization with CagA-negative strains was not (OR, 1.08; 95% CI, 0.76-1.53). For esophageal squamous cell carcinoma, the summary OR (95% CI) was 1.10 (0.78-1.55). However, there was substantial heterogeneity among studies (I(2) = 73%), with statistically significant associations in both directions. Our results suggest an inverse association between CagA-positive H. pylori colonization and risk of EAC. The prominent decline of H. pylori colonization in the past few decades may be partly responsible for the recent increase in EAC incidence in Western countries.