Clostridioides Difficile in Latin America: An Epidemiological Overview.

Clostridioides difficile infection is one of the most significant causes of nosocomial diarrhea associated with antibiotic use worldwide. In recent years, the incidence of Clostridioides difficile infection in Latin American countries has increased due to the emergence and spread of epidemic Clostridioides difficile strains, such as RT027/NAP1/ST1, RT078/ST11, and RT017/ST37; additionally, endemic multi-drug-resistant strains have recently appeared due to the lack of heterogeneous diagnostic algorithms and guidelines for antibiotic use in each country. The aim of this review is to present the latest information regarding Clostridioides difficile and emphasize the importance of epidemiological surveillance of this pathogen in Latin American countries.

Genomic insights of Leclercia adecarboxylata strains linked to an outbreak in public hospitals in Mexico.

BACKGROUND: Leclercia adecarboxylata is a bacteria closely related to Escherichia coli according to its biochemical characteristics and is commonly considered non-pathogenic although a growing number of publications classify it as an emerging pathogen. Fosfomycin resistance is a common trait for L. adecarboxylata encoded by fosALA gene. OBJECTIVE: To analyze genomic traits of sixteen L. adecarboxylata strains isolated from blood culture and a bottle of total parenteral nutrition. METHODS: Twenty-eight L. adecarboxylata strains isolated from blood culture and a bottle of total parenteral nutrition were identified biochemically with a Vitek ® automated system. The strains were phenotyped by their growth on Eosin Methylene Blue agar or MacConkey agar plates. Additionally, Pulsed field gel electrophoresis (PFGE) was performed to establish the clonal relationship. The genomic DNA of sixteen strains was obtained using a Qubit ® dsDNA HS Assay Kit and sequenced on an Illumina ® MiSeq instrument. Draft genomes were assembled using PROKKA and Rast. Assemblies were submitted to Resfinder and PathogenFinder from the Center for Genomic Epidemiology in order to find resistance genes and pathogenic potential. IslandViewer4 was also used to find Pathogenicity and Phage Islands. For identification of the fosA gene, manual curation and Clustal analysis was performed. A novel FosA variant was identified. Finally, phylogenetic analysis was performed using VAMPhyRE software and Mega X. RESULTS: In this paper, we report the genomes of sixteen strains of Leclercia adecarboxylata causing an outbreak associated with parenteral nutrition in public hospitals in Mexico. The genomes were analyzed for genetic determinants of virulence and resistance. A high pathogenic potential (pathogenicity index 0.82) as well as multiple resistance genes including carbapenemics, colistin and efflux pumps were determined. Based on sequence analysis, a new variant of the fosALA gene was described. Finally, the outbreak was confirmed by establishing the clonal relationship among the sixteen genomes obtained. CONCLUSIONS: Commensal strains of L. adecarboxylata may acquire genetic determinants that provide mechanisms of host damage and go unnoticed in clinical diagnosis. L. adecarboxylata can evolve in a variety of ways including the acquisition of resistance and virulence genes representing a therapeutic challenge in patient care.

Phylogenetic origin of Helicobacter pylori pathogenicity island and risk of stomach cancer and high-grade premalignant gastric lesions.

Infection by Helicobacter pylori (Hp) has been causally linked to risk of gastric cancer (GC). The coevolution of Hp and humans shaped the risk of GC as our species left Africa and migrated to the other continents. Latin America (LatAm) is a high GC incidence region where Hp evolved uniquely in the 500 years since European colonization. Differential virulence of the Hp cagA -pathogenicity island (cagPAI) by ancestral origin has been reported. We hypothesized that Hp phylogenetic origin might play a role in determining GC risk in LatAm. We used genotypes of 50 Hp genetic variants mapping to the Hp cagPAI, studied in 1220 subjects from Venezuela, Colombia, Mexico and Paraguay, who were infected with cagA-positive Hp, including 150 GC, 177 high-grade premalignant lesions (HGPMLs) and 893 low-grade premalignant lesions. We estimated the phylogenetic origin of Hp cagPAI in all study subjects by use of the STRUCTURE software and principal component analysis (PCA) and tested whether the estimated African ancestry percentage was associated with the risk of GC or HGPML. African ancestral component estimates by STRUCTURE and PCA were highly correlated. STRUCTURE-based African origin estimate was not significantly associated with the risk of HGPML, but it was inversely associated with GC risk: the OR associated with the continuous values of African component was 0.09 (95% CI, 0.01-0.85; P = 0.035). Similar trends were observed for GC with PCA-based estimates, but the association was not statistically significant. These results suggest that Hp ancestral origin may play a role in gastric carcinogenesis.

Copy number alterations and epithelial­mesenchymal transition genes in diffuse and intestinal gastric cancers in Mexican patients.

Gastric cancer (GC) is a common malignancy with the highest mortality rate among diseases of the digestive system, worldwide. The present study of GC alterations is crucial to the understanding of tumor biology and the establishment of important aspects of cancer prognosis and treatment response. In the present study, DNA from Mexican patients with diffuse GC (DGC), intestinal GC (IGC) or non­atrophic gastritis (NAG; control) was purified and whole­genome analysis was performed with high­density arrays. Shared and unique copy number alterations (CNA) were identified between the different tissues involving key genes and signaling pathways associated with cancer. This led to the molecular distinction and identification of the most relevant molecular functions to be identified. A more detailed bioinformatics analysis of epithelial­mesenchymal transition (EMT) genes revealed that the altered network associated with chromosomal alterations included 11 genes that were shared between DGC, IGC and NAG, as well as 19 DGC­ and 7 IGC­exclusive genes. Furthermore, the main molecular functions included adhesion, angiogenesis, migration, metastasis, morphogenesis, proliferation and survival. The present study provided the first whole­genome high­density array analysis in Mexican patients with GC and revealed shared and exclusive CNA­associated genes in DGC and IGC. In addition, a bioinformatics­predicted network was generated, focusing on CNA­altered genes associated with EMT and the hallmarks of cancer, as well as precancerous alterations that may lead to GC. Molecular signatures of diffuse and intestinal GC, predicted bioinformatically, involve common and distinct CNA­EMT genes related to the hallmarks of cancer that are potential candidates for screening biomarkers of GC, including early stages.

Colostrum IgA1 antibodies recognize antigens from Helicobacter pylori and prevent cytoskeletal changesin human epithelial cells.

Helicobacter pylori is a Gram-negative bacterium found on the luminal surface of the gastric mucosa in at least 50% of the world's human population. The protective effect of breastfeeding against H. pylori infection has been extensively reported; however, the mechanisms behind this protection remain poorly understood. Human IgA from colostrum has reactivity against H. pylori antigens. Despite that IgA1 and IgA2 display structural and functional differences, their reactivity against H. pylori had not been previously determined. We attested titers and reactivity of human colostrum-IgA subclasses by ELISA, immunoblot, and flow cytometry. Colostrum samples from healthy mothers had higher titers of IgA; and IgA1 mostly recognized H. pylori antigens. Moreover, we found a correlation between IgA1 reactivity and their neutralizing effect determined by inhibition of cytoskeletal changes in AGS cells infected with H. pylori. In conclusion, colostrum-IgA reduces H. pylori infection of epithelial gastric cells, suggesting an important role in preventing the bacteria establishment during the first months of life. As a whole, these results suggest that IgA1 from human colostrum provides protection that may help in the development of the mucosal immune system of newborn children.

Molecular Epidemiology and Antimicrobial Resistance of Clostridioides difficile in Hospitalized Patients From Mexico.

Clostridioides difficile is a global public health problem, which is a primary cause of antibiotic-associated diarrhea in humans. The emergence of hypervirulent and antibiotic-resistant strains is associated with the increased incidence and severity of the disease. There are limited studies on genomic characterization of C. difficile in Latin America. We aimed to learn about the molecular epidemiology and antimicrobial resistance in C. difficile strains from adults and children in hospitals of México. We studied 94 C. difficile isolates from seven hospitals in Mexico City from 2014 to 2018. Whole-genome sequencing (WGS) was used to determine the genotype and examine the toxigenic profiles. Susceptibility to antibiotics was determined by E-test. Multilocus sequence typing (MLST) was used to determine allelic profiles. Results identified 20 different sequence types (ST) in the 94 isolates, mostly clade 2 and clade 1. ST1 was predominant in isolates from adult and children. Toxigenic strains comprised 87.2% of the isolates that were combinations of tcdAB and cdtAB (tcdA+/tcdB+/cdtA+/cdtB+, followed by tcdA+/tcdB+/cdtA-/cdtB-, tcdA-/tcdB+/cdtA-/ cdtB-, and tcdA-/tcdB-/cdtA+/cdtB+). Toxin profiles were more diverse in isolates from children. All 94 isolates were susceptible to metronidazole and vancomycin, whereas a considerable number of isolates were resistant to clindamycin, fluroquinolones, rifampicin, meropenem, and linezolid. Multidrug-resistant isolates (≥3 antibiotics) comprised 65% of the isolates. The correlation between resistant genotypes and phenotypes was evaluated by the kappa test. Mutations in rpoB and rpoC showed moderate concordance with resistance to rifampicin and mutations in fusA substantial concordance with fusidic acid resistance. cfrE, a gene recently described in one Mexican isolate, was present in 65% of strains linezolid resistant, all ST1 organisms. WGS is a powerful tool to genotype and characterize virulence and antibiotic susceptibility patterns.

Detection of Epstein-Barr Virus DNA in Gastric Biopsies of Pediatric Patients with Dyspepsia.

In this study, we assessed the presence of Epstein-Barr virus (EBV) in gastric samples derived from pediatric patients with dyspeptic symptoms, aiming to understand whether EBV participates in the development of early gastric lesions influencing chronic inflammation, in conjunction with the Helicobacter pylori (Hp) bacterium. We analyzed EBV load in 236 gastric biopsies derived from 186 pediatric patients with chronic dyspepsia and compared it with EBV serology, Hp load and serology, and with immune cell infiltration. We found that 7.5% of patients were positive for EBV load, ranging from 240 to 29,685 genomic copies/µg of DNA. Hp genomic sequences were found in 24.7% of patients. EBV positive samples did not correlate with Hp status and were characterized by absent to moderate immune cell infiltration. To our knowledge, this is the first study addressing EBV load in the stomach in a large cohort of pediatric patients with dyspeptic symptoms, providing evidence of EBV localization in the gastric mucosa in early inflammatory lesions. The lack of correlation between EBV and both Hp infection and inflammation is perhaps explained by independent pathogenic mechanisms or because of the randomness of the gastritis sampling. This is also supported by a moderate association between EBV load and serology.

Genetic polymorphisms in the cag pathogenicity island of Helicobacter pylori and risk of stomach cancer and high-grade premalignant gastric lesions.

Helicobacter pylori (Hp) infects the stomach of about half of the human population and is strongly associated with the risk of gastric cancer (GC) and its premalignant precursors. The cag pathogenicity island (cagPAI) is a region of the Hp genome encoding for key molecular machinery involved in the infection process. Following a sequencing study, we selected 50 genetic polymorphisms located in seven cagPAI genes and tested their associations with the risk of advanced gastric premalignant lesions and GC in 1220 subjects from various Latin American populations showing the whole spectrum of phenotypes from gastritis to GC. We found that three polymorphisms of cagA are associated with the risk of advanced gastric premalignant lesions (incomplete intestinal metaplasia [ie, Type 2 and 3] or dysplasia), and that six polymorphisms located in cagA, cagL and cagI were associated with risk of GC. When corrected for multiple testing none of the associations were statistically significant. However, scores built by integrating the individual polymorphisms were significantly associated with the risk of advanced gastric premalignant lesions and GC. These results have the potential of establishing markers for risk stratification in the general population, in view of targeting Hp eradication to high-risk population groups.

Variations in cag pathogenicity island genes of Helicobacter pylori from Latin American groups may influence neoplastic progression to gastric cancer.

Helicobacter pylori (HP) colonizes the human stomach and induces acute gastritis, peptic ulcer disease, atrophic gastritis, and gastric adenocarcinoma. Increased virulence in HP isolates derives from harboring the cag (cytotoxin-associated genes) pathogenicity island (cagPAI). We analyzed the microvariants in cagPAI genes with the hypothesis that they may play an important role in determining HP virulence. We tested DNAs from cagA positive patients HP isolates; a total of 74 patients with chronic gastritis (CG, N = 37), intestinal metaplasia (IM, N = 21) or gastric cancer (GC, N = 16) from Mexico and Colombia. We selected 520 non-synonymous variants with at least 7.5% frequency in the original sequence outputs or with a minimum of 5 isolates with minor allele. After adjustment for multiple comparisons, no variants were statistically significantly associated with IM or GC. However, 19 non-synonymous showed conventional P-values < 0.05 comparing the frequency of the alleles between the isolates from subjects with gastritis and isolates from subjects with IM or GC; 12 of these showed a significant correlation with the severity of the disease. The present study revealed that several cagPAI genes from Latin American Western HP strains contains a number of non-synonymous variants in relatively high frequencies which could influence on the clinical outcome. However, none of the associations remained statistically significant after adjustment for multiple comparison.

Phenotypic and Genotypic Antibiotic Resistance Patterns in Helicobacter pylori Strains From Ethnically Diverse Population in México.

Helicobacter pylori strains carry a range of mutations in genes that confer antimicrobial resistance and restrict the available options to treat the infection. Latin America is a region that conserve a large number of indigenous communities relatively isolated that practice a traditional medicine without consumption of drugs. We hypothesized that rates of antibiotic resistance are lower in these communities. Recent progress in whole-genome sequencing has allowed the study of drug susceptibility by searching for the known mutations associated with antibiotic resistance. The aim of this work was to study trends of antibiotic resistance over a 20-year period in Mexican H. pylori strains and to compare susceptibility between strains from Mexican mestizos and from indigenous population; we also aimed to learn the prevalence of mutational patterns in genes gyrA, gyrB, rdxA, frxA, rpsU, omp11, dppA, and 23S rRNA and its association with phenotypic tests. Resistance to clarithromycin, metronidazole, amoxicillin and levofloxacin was determined in167 H. pylori isolates by E-test, and the occurrence of mutational patterns in specific genes was determined by whole genome sequencing (WGS). The trend of resistance over 20 years in mestizo isolates showed significant resistant increase for clarithromycin and levofloxacin to frequencies that banned its clinical use. Resistance in H. pylori isolates of native communities was lower for all antibiotics tested. Phenotypic resistance showed good to moderate correlation with genotypic tests. Genetic methods for characterizing antibiotic resistance require further validation in each population.

Risk factors for gastric precancerous and cancers lesions in Latin American counties with difference gastric cancer risk.

OBJECTIVE: To evaluate the risk factors associated with pre-neoplastic lesions and gastric cancer in countries with different cancer risk in Latin America. METHODS: 1222 questionnaires of risk factors related to pre-neoplastic lesions and gastric cancer were obtained from patients from Mexico (N = 559), Colombia (N = 461) and Paraguay (N = 202), who were treated at the gastroenterology or oncology service of participant hospitals. In addition, biopsies specimens to establish histological diagnosis and blood to detect IgG antibodies against Helicobacter-pylori (H. pylori) whole-cell antigens and CagA protein using an ELISA were collected. These consisted of 205 gastric cancer, 379 pre-neoplastic (intestinal metaplasia (IM) / atrophic gastritis) and 638 control (normal /non-atrophic gastritis) cases. The odds ratio (OR) and 95% confidence intervals (CI) associated with potential risk factors were estimated by polynomial logistic regression model. RESULTS: Seropositivity to H. pylori was associated with risk of pre-neoplastic lesions, with OR = 1.9 (CI 95% 1.2-2.9; p = 0.006). Grain / cereal intake (OR = 1.6, 95% CI 1.0-2.5 ; p = 0.049) and egg intake (OR = 1.7 95% CI 1.1-2.6 ; p = 0.021) were related to gastric cancer. Among, people who did not developed gastric cancer, smoking more than five cigarette per day had the highest risk of being infected by H. pylori (OR = 1.9; CI 95% 1.1-3.3 ; p = 0.028). CONCLUSION: The present study in Latin American countries confirmed that similar environmental factors such as smoking and grain/cereal consumption were associated with H. pylori infection and its induced gastric lesions as reported in other regions where dominant H. pylori strains differ.

Potential Role of Biofilm Formation in the Development of Digestive Tract Cancer With Special Reference to Helicobacter pylori Infection.

Bacteria are highly social organisms that communicate via signaling molecules and can assume a multicellular lifestyle to build biofilm communities. Until recently, complications from biofilm-associated infection have been primarily ascribed to increased bacterial resistance to antibiotics and host immune evasion, leading to persistent infection. In this theory and hypothesis article we present a relatively new argument that biofilm formation has potential etiological role in the development of digestive tract cancer. First, we summarize recent new findings suggesting the potential link between bacterial biofilm and various types of cancer to build the foundation of our hypothesis. To date, evidence has been particularly convincing for colorectal cancer and its precursor, i.e., polyps, pointing to several key individual bacterial species, such as Bacteroides fragilis, Fusobacterium nucleatum, and Streptococcus gallolyticus subsp. Gallolyticus. Then, we further extend this hypothesis to one of the most common bacterial infection in humans, Helicobacter pylori (Hp), which is considered a major cause of gastric cancer. Thus far, there has been no direct evidence linking in vivo Hp gastric biofilm formation to gastric carcinogenesis. Yet, we synthesize the information to support an argument that biofilm associated-Hp is potentially more carcinogenic, summarizing biological characteristics of biofilm-associated bacteria. We also discuss mechanistic pathways as to how Hp or other biofilm-associated bacteria control biofilm formation and highlight recent findings on Hp genes that influence biofilm formation, which may lead to strain variability in biofilm formation. This knowledge may open a possibility of developing targeted intervention. We conclude, however, that this field is still in its infancy. To test the hypothesis rigorously and to link it ultimately to gastric pathologies (e.g., premalignant lesions and cancer), studies are needed to learn more about Hp biofilms, such as compositions and biological properties of extracellular polymeric substance (EPS), presence of non-Hp microbiome and geographical distribution of biofilms in relation to gastric gland types and structures. Identification of specific Hp strains with enhanced biofilm formation would be helpful not only for screening patients at high risk for sequelae from Hp infection, but also for development of new antibiotics to avoid resistance, regardless of its association with gastric cancer.

Polymorphisms in IL-10 and TGF-ß gene promoter are associated with lower risk to gastric cancer in a Mexican population.

BACKGROUND: Helicobacter pylori infection is recognized as the main risk factor for gastric cancer (GC), the fifth most common neoplasia worldwide. H. pylori interacts with the immune system, disrupting the cytokine network and inducing chronic inflammation. This work aimed to evaluate the association between single nucleotide polymorphisms (SNPs) in selected cytokine gene promoters and GC. METHODS: The study included 359 subjects, 125 GC patients, 109 intestinal metaplasia (IM) patients and 125 asymptomatic controls. DNA was extracted from white blood cells and nine SNPs in cytokine gene promoters were genotyped using predesigned 5'-endonulease assays. The association of the SNPs with IM and GC was evaluated using multinomial regression models. RESULTS: Both genotypes, TC (OR = 0.51, 95% CI = 0.27-0.98) and TT (OR = 0.42, 95% CI = 0.20-0.91) in the locus - 509 of the TGF-ß promoter were significantly associated with GC. The TT genotype in the locus - 819 of the IL-10 promoter was also significantly associated with GC (OR = 0.37, 95% CI = 0.17-0.81). No significant association was found with SNPs IL-4 -590 T/C (rs1800629), IL-6 -573G/C (rs1800796), IL-10 -592C/A (rs1800872), IL-10 -1082A/G (rs1800896), and, IFN-γ -1615C/T (rs2069705). CONCLUSIONS: SNPs in TGFß (- 509 C/T, rs1800469) and IL-10 (- 819 C/T, rs1800871) promoters were associated with a lower risk for GC in a Mexican population.

Development and validation of a whole-cell ELISA for serologically diagnosing Helicobacter pylori infection in Brazilian children and adults: a diagnostic accuracy study.

BACKGROUND: Serological tests are practical, with low cost, but no noninvasive tests are available for diagnosing Helicobacter pylori (H. pylori) infection in Brazil. The aim here was to develop and validate enzyme-linked immunosorbent assay (ELISA) serological tests to detect anti-H. pylori immunoglobulin G antibodies, based on cultured strains from Brazilian patients. DESIGN AND SETTING: Cross-sectional, diagnostic accuracy study comparing a locally developed and validated ELISA and invasive tests among dyspeptic patients at two public hospitals in São Paulo, Brazil. METHODS: An ELISA test was prepared using whole-cell antigen from 56 strains. After genotypic characterization, it was standardized and optical density (OD) cutoffs were determined based on the serum antibody response of 100 H. pylori-negative samples, compared with 82 H. pylori-positive samples. Validation was performed on 174 symptomatic patients. RESULTS: The optimal OD cutoffs established (for monoclonal and polyclonal tests, respectively) were 0.167 and 0.164; overall ELISA sensitivity: 84.3%, 78.9%; specificity: 88.6%, 90.6%; positive predictive value (PPV): 75.4%, 80%; negative predictive value (NPV): 93.1%, 81.8%; accuracy: 87.3%, 86.2%; child and adolescent ELISA sensitivity: 74.2%, 81.8%; specificity: 90.8%, 86.7%; PPV: 66.6%, 84.3%; NPV: 95.8%, 84.8%; accuracy: 88.5%, 84.6; adult ELISA sensitivity: 84.4%, 75%; specificity: 86.9%, 93%; PPV: 81.8%, 78.3%; NPV: 88.9%, 91.8%; accuracy: 85.9%, 88.5%. CONCLUSION: The polyclonal serological test developed using local strains presented better diagnostic performance among children and adolescents, while the monoclonal test was better among adults. The results from both tests suggest that these in-house serological tests could be used to detect anti-H. pylori antibodies in our population, for screening purposes.

Genotype B of Killer Cell Immunoglobulin-Like Receptor is Related with Gastric Cancer Lesions.

NK cells are important in innate immunity for their capacity to kill infected or cancer cells. The killer cell immunoglobulin-like receptors (KIR) are a family of polymorphic genes with inhibitory and activating functions. The main driving force for gastric cancer (GC) development is a chronic response, which causes an increase of NK cells in the gastric mucosa. The aim of this work was to study polymorphisms in KIR genes in patients with either GC or non-atrophic gastritis (NAG). We studied 242 patients (130 with NAG and 112 with GC) and contrasted with 146 asymptomatic individuals. We analyzed diversity in the content and localization of KIR genes in the different clinical groups studied. Four activating and one inhibitory genes were associated with GC: 2DS1 (OR 3.41), 2DS3 (OR 4.66), 2DS5 (OR 2.25), 3DS1 (OR 3.35) and 2DL5 (OR 3.6). The following were also found as risk factors for GC: Bx genotype (OR 4.2), Bx-Bx centromere-telomere (OR 2.55), cA01|cB03 (OR 36.39) and tB01|tB01 (OR 7.55) gene content and three B motifs (OR 10.9). Polymorphisms in KIR genes were associated with GC and suggest that mutated NK cells may contribute to GC development by increasing gastric mucosa inflammation, leading to constant tissue damage.

Erratum: A proposed method for the relative quantification of levels of circulating microRNAs in the plasma of gastric cancer patients.

[This corrects the article DOI: 10.3892/ol.2017.5816.].

Circulating blood levels of IL-6, IFN-γ, and IL-10 as potential diagnostic biomarkers in gastric cancer: a controlled study.

BACKGROUND: Gastric adenocarcinoma is the third most common cause of cancer-associated death worldwide. Helicobacter pylori infection activates a signaling cascade that induces production of cytokines and chemokines involved in the chronic inflammatory response that drives carcinogenesis. We evaluated circulating cytokines and chemokines as potential diagnostic biomarkers for gastric cancer. METHODS: We included 201 healthy controls and 162 patients with distal gastric cancer who underwent primary surgical resection between 2009 and 2012 in Mexico City. The clinical and pathological data of patients were recorded by questionnaire, and the cancer subtype was classified as intestinal or diffuse. Pathological staging of cancer was based on the tumor-node-metastasis staging system of the International Union Against Cancer. Concentrations of IL-1ß, IL-6, TNF-α, IL-10, and MCP-1 in serum were measured using multiplex analyte profiling technology and concentrations of IL-8, IFN-γ, and TGF-ß in plasma were measured using enzyme-linked immunosorbent assay. RESULTS: Levels of IL-1ß, IL-6, IFN-γ, and IL-10 were significantly higher and that of MCP-1 was lower in gastric cancer patients compared with controls. No differences in IL-8 or TNF-α levels were observed between gastric cancer and controls. IFN-γ and IL-10 were significantly higher in both intestinal and diffuse gastric cancer, whereas IL-1ß and IL-6 were higher and TGF-ß lower only in intestinal gastric cancer; MCP-1 was lower only in diffuse gastric cancer. IFN-γ and IL-10 levels were significantly higher in early (I/II) and late stage (III/IV) gastric cancer; IL-1ß and IL-8 were higher and MCP-1 was lower only in late stage (IV) patients. Receiver-operating characteristic analysis showed that for diagnosis of GC, IL-6 had high specificity (0.97) and low sensitivity (0.39), IL-10 had moderate specificity (0.82) and low sensitivity (0.48), and IL-1ß and IFN-γ showed low specificity (0.43 and 0.53, respectively) and moderate sensitivity (0.76 and 0.71, respectively). CONCLUSIONS: Increased levels of IL-6, IFN-γ, and IL-10 might be useful as diagnostic biomarkers for GC; however, this needs to be confirmed with larger number of patients and with control groups other than blood donors, properly age paired. IL-1ß, IL-6, MCP-1, and TGF-ß differentiate intestinal from diffuse GC. IFN-γ and IL-10 might be useful for diagnosis of early stage GC, and IL-1ß, IL-8, and MCP-1 for late stages of the disease.

A proposed method for the relative quantification of levels of circulating microRNAs in the plasma of gastric cancer patients.

Gastric cancer (GC) is the fifth most common type of malignancy and the third leading cause of cancer-associated mortality worldwide. It is necessary to identify novel methods aimed at improving the early diagnosis and treatment of GC. MicroRNA expression profiles in the plasma of patients with GC have demonstrated a potential use in the opportune diagnosis of this neoplasm. However, there are currently no standardized targets for use in the normalization of microRNA Cq values for different neoplasms. The present study tested two normalization approaches while analyzing plasma derived from patients with GC and non-atrophic gastritis. The first method utilized a panel of small nucleolar RNAs (snoRNAs) and a small nuclear RNA (snRNA) provided by a commercial array. The second normalization approach involved the use of hsa-miR-18a-5p and hsa-miR-29a-3p, which were identified by a stability analysis of the samples being tested. The results revealed that the snoRNAs and snRNA were not expressed in all samples tested. Only the stable microRNAs allowed a narrow distribution of the data and enabled the identification of specific downregulation of hsa-miR-200c-3p and hsa-miR-26b-5p in patients with GC. hsa-miR-200c-3p and hsa-miR-26b-5p have been previously linked to cancer, and a Kyoto Encyclopedia of Genes and Genomes analysis demonstrated that these microRNAs were associated with cell adhesion, cell cycle and cancer pathways.

Helicobacter pylori vacA s1m1 genotype but not cagA or babA2 increase the risk of ulcer and gastric cancer in patients from Southern Mexico.

BACKGROUND: The vacA, cagA and babA2 genotypes of Helicobacter pylori are associated with gastric pathology. The objectives were to determine the frequency of infection and distribution of the vacA, cagA and babA2 genotypes of H. pylori in patients with gastric ulcer, chronic gastritis and gastric cancer, and to evaluate the association of virulent genotypes with diagnosis. METHODS: We studied 921 patients with symptoms of dyspepsia or with presumptive diagnosis of gastric cancer. The DNA of H. pylori and the vacA, cagA and babA2 genes was detected by PCR in total DNA from gastric biopsies. The association of H. pylori and of its cagA, vacA and babA2 genotypes with diagnosis was determined by calculating the odds ratio (OR). RESULTS: Chronic gastritis was confirmed in 767 patients, gastric ulcer in 115 and cancer in 39. The prevalence of H. pylori was 47.8, 49.6 and 61.5% in those groups, respectively. H. pylori was more frequent in the surrounding tissue (69.2%) than in the tumor (53.8%). The vacA s1m1 genotype predominated in the three groups (45.2, 61.4 and 83.3%, respectively). H. pylori was associated with cancer (ORadjusted = 2.08; 95% CI 1.05-4.13; p = 0.035) but not with ulcer (ORadjusted = 1.07; 95% CI 0.71-1.61; p = 0.728). The s1m1 genotype was associated with ulcer and cancer (ORadjusted = 2.02; 95% CI 1.12-3.62; p = 0.019 and ORadjusted = 6.58; 95% CI 2.15-20.08; p = 0.001, respectively). babA2 was associated with gastric cancer, and cagA was not associated with the diagnosis. CONCLUSIONS: In population from Southern Mexico, H. pylori and the s1m1 genotype were associated with gastric cancer and the s1m1/cagA+/babA2+ strains predominated in tumor and adjacent tissue.