Prevalence of Helicobacter pylori infection in advanced gastric carcinoma

Association of Helicobacter Pylori in Carcinoma Stomach at Maharaja Krishna Chandra Gajapat Medical College: A Prospective Study

Introduction

Gastric cancer is the fourth most common type of cancer and the second leading cause of cancer-related death in the world. The etiology of gastric cancer includes Helicobacter pylori infection, diet, lifestyle, tobacco, alcohol, and genetic susceptibility. Upper gastrointestinal endoscopy (UGIE) is the most effective method for examining the upper gastrointestinal tract as compared to the other examination tools.

Objective

To study the histopathological finding of upper gastrointestinal endoscopic biopsies and its association with H. pylori in cases of carcinoma stomach.

Materials and methods

This was a hospital-based observational study carried out in the Department of Surgery, at Maharaja Krushna Chandra Gajapati Medical College, Berhampur, a tertiary care hospital in Eastern India. Study population consisted of 106 patients for a period of 2 years from July 2019 to June 2021, after due consideration of the inclusion and exclusion criteria. Endoscopic location and pathological types of the gastric lesion were noted, and all biopsy specimens were investigated to see the presence of H. pylori by rapid urease test (RUT) and histological examination in the form of Giemsa and H&E stain.

Results

In the present study of 106 cases, 62 cases (58.49%) were found to be positive for H. Pylori by RUT and 72 cases (67.92%) were positive for H. pylori by smear staining. In histopathological study, 72 cases (67.92%) were of intestinal type of carcinoma and 34 cases (32.07%) were of diffuse type of carcinoma. Smear for H. pylori was positive in 56 cases (77.78%) among the 72 cases of intestinal type of carcinoma stomach. Whereas only 16 cases (47.05%) were found to be smear-positive for H. pylori among the 34 cases of diffuse type of lesion. Irrespective of histological type, H. pylori was positive in 67.92% of patients with carcinoma stomach. This association was statistically significant (p<0.001) and indicates its role in intestinal type of gastric carcinoma.

Conclusion

There is a high frequency of H. pylori infection in cases of stomach cancer. This study confirmed the higher association of H. pylori infection with gastric cancer. Its association with the intestinal histological variety of stomach cancer is more common than diffuse type. The prevalence of H. pylori infection in distal stomach carcinoma is higher than proximal.

The immune microenvironment in gastric adenocarcinoma

Like most solid tumours, the microenvironment of epithelial-derived gastric adenocarcinoma (GAC) consists of a variety of stromal cell types, including fibroblasts, and neuronal, endothelial and immune cells. In this article, we review the role of the immune microenvironment in the progression of chronic inflammation to GAC, primarily the immune microenvironment driven by the gram-negative bacterial species Helicobacter pylori. The infection-driven nature of most GACs has renewed awareness of the immune microenvironment and its effect on tumour development and progression. About 75-90% of GACs are associated with prior H. pylori infection and 5-10% with Epstein-Barr virus infection. Although 50% of the world's population is infected with H. pylori, only 1-3% will progress to GAC, with progression the result of a combination of the H. pylori strain, host susceptibility and composition of the chronic inflammatory response. Other environmental risk factors include exposure to a high-salt diet and nitrates. Genetically, chromosome instability occurs in ~50% of GACs and 21% of GACs are microsatellite instability-high tumours. Here, we review the timeline and pathogenesis of the events triggered by H. pylori that can create an immunosuppressive microenvironment by modulating the host's innate and adaptive immune responses, and subsequently favour GAC development.

HELICOBACTER PYLORI cagA VIRULENCE GENE AND SEVERE ESOGASTRODUODENAL DISEASES: IS THERE AN ASSOCIATION?

BACKGROUND

Helicobacter pylori colonizes approximately half of the world's human population. Its presence in the gastric mucosa is associated with an increased risk of gastric adenocarcinoma, gastric lymphoma, and peptic ulcer disease. In Brazil, the high prevalence of H. pylori infection is a serious health problem. H. pylori virulence factors are associated with an increased risk of serious gastrointestinal disorders. The cagA gene encodes a cytotoxin-A-associated antigen (CagA) that is involved in bacterial pathogenicity. H. pylori strains carrying the cag pathogenicity island (cag-PAI) are significantly associated with severe clinical outcomes and histopathological changes.

OBJECTIVE

The present study aims to investigate the prevalence of the cagA gene among H. pylori isolates from patients with different gastric pathologies. Further, the study hopes to verify its association with clinical outcomes. In addition, phylogenetic analysis was performed on cagA-positive H. pylori strains from patients with severe and non-severe diseases.

METHODS

Gastric specimens were collected through a biopsy from 117 patients with different esogastroduodenal diseases. DNA was extracted from these gastric specimens and the polymerase chain reaction was performed to amplify the gene fragments corresponding to the 16S ribosomal RNA and cagA genes using specific primers. The polymerase chain reaction products of selected samples positive for cagA were sequenced. The sequences were aligned with reference sequences from the National Center for Biotechnology Information (NCBI) (Bethesda/USA), and a phylogenetic tree was constructed.

RESULTS

H. pylori was detected in 65.9% (77/117) of Brazilian patients with different gastroduodenal disorders. Overall, 80.5% (62/77) of the strains were cagA-positive. The ages of patients with cagA-positive strains (15 males and 47 females) ranged from 18 to 74 years. The lesions were categorized as non-severe and severe according to the endoscopic and histopathological reports the most prevalent non-severe esogastroduodenal lesion was gastritis 54/77 (70.12%), followed by esophagitis 12/77 (15.58%) and duodenitis 12/77 (15.58%). In contrast, the most prevalent severe lesions were atrophy 7/77 (9.09%), followed by metaplasia 3/77 (3.86%) and gastric adenocarcinoma 2/77 (2.59%). Phylogenetic analyses performed with the partial sequences of the cagA gene obtained from local strains were grouped in the same clade. No differences in phylogenetic distribution was detected between severe and non-severe diseases.

CONCLUSION

The cagA gene is highly prevalent among H. pylori isolates from gastric lesions in Brazilian patients. The presence of the cagA gene was not considered a marker of the severity of esogastroduodenal lesions in the present study. This is the first study to investigate the phylogenetic population structure of H. pylori strains in a Brazilian capital, which may improve our understanding of the clinical outcome of H. pylori infection.

HELICOBACTER PYLORI INFECTION IN PATIENTS WITH DIFFERENT GASTROINTESTINAL DISEASES FROM NORTHERN BRAZIL

BACKGROUND

The mechanisms whereby Helicobacter pylori produces different pathological manifestations in the stomach and duodenum are not fully understood. Considering the geographic diversity in the prevalence of virulence factors of this microorganism and their association with the development of different diseases, the search for pathogenicity markers such as CagA and VacA alleles by molecular techniques has intensified.

OBJECTIVES

To investigate the presence of H. pylori infection and the frequency of different genotypes of this bacterium in patients with gastrointestinal diseases from Northern Brazil, and to establish their association with the histopathological findings.

METHODS

In a prospective study, samples were collected from 554 patients with different gastrointestinal diseases (gastritis, duodenal ulcer, gastric ulcer, and gastric cancer) seen at a referral hospital attending the entire State of Pará, located in the metropolitan region of Belém. Data such as gender and age obtained with an epidemiological questionnaire were analyzed. The presence of H. pylori and the bacterial genotype were investigated by PCR. Gastric biopsies were assessed histologically.

RESULTS

The prevalence of H. pylori infection was 91%. Infection was more frequent among patients with gastric ulcer and gastric cancer. In these groups, there was a predominance of men and older patients when compared to the other two groups studied. The predominant bacterial genotype was s1m1cagA+, which was more frequent among patients with gastric ulcer, duodenal ulcer and gastric cancer. A significant association was observed between s1m1cagA+ strains and a higher degree of inflammation, neutrophil activity and development of intestinal metaplasia.

CONCLUSION

The present study demonstrates a high incidence of H. pylori infection in the patients analyzed, especially among those with gastric ulcer and gastric cancer. Virulent s1m1cagA+ strains predominated and were associated with more severe lesions.

Case study of stomach adenocarcinoma conducted at a cancer referral hospital in northern Brazil

CONTEXT

Stomach cancer is the second leading cause of death due to cancer in the world and the incidence of this disease continues to be high in Brazil. In the Northern region, gastric cancer is the second most frequent cancer among men and the third among women. In the State of Pará, stomach adenocarcinoma is a public health problem since mortality rates are above the Brazilian average.

OBJECTIVE

To analyze the clinical and anatomopathological profile of stomach adenocarcinoma in patients seen at Ofir Loiola Hospital.

METHODS

In a retrospective study, records from 302 patients with gastric cancer undergoing surgery between 2006 and 2008 were analyzed. Data regarding patient profile, early symptoms, alterations upon physical examination, type of surgery, and macroscopic and histological findings were obtained from the records.

RESULTS

Most patients (63.9%) were men, 48% were older than 60 years, 50.9% were from the metropolitan region of Belém, 68.2% presented epigastric pain as an early symptom, and abdominal tenderness upon palpation was observed in 63.7%. The antrum was the most affected anatomical site (62.1%), followed by the gastric body (26.9%). Borrmann III (ulcerated-infiltrative) was the predominant endoscopic type. Adenocarcinoma accounted for 95.4% of all cases, including the intestinal type in 56.6% and the diffuse type in 41.3%. Most patients had stage IIIB and IV tumors and total gastrectomy was the most frequent type of surgery (37.4%).

CONCLUSION

The present study demonstrated that gastric adenocarcinoma mainly affected men over the age of 60 who were from the metropolitan region of Belém. Most adenocarcinomas were in an advanced stage at the time of diagnosis, a fact requiring more aggressive surgical resection in these cases. These data highlight the urgent need for the implementation of preventive measures and early detection programs of gastric cancer.

The relationship between Helicobacter pylori infection and the effects of chemotherapy in patients with advanced or metastatic gastric cancer

PURPOSE

Several reports have shown a better prognosis in gastric cancer patients who are positive for Helicobacter pylori (HP) infection compared with negative cases. However, there are currently no studies that investigate the relationship between HP infection and the effects of chemotherapy in gastric cancer patients. In this study, we report the relationship between HP infection and chemotherapy effects in patients with advanced or metastatic gastric cancer.

METHODS

Sixty-one patients with advanced or metastatic gastric cancer were enrolled in this study. Biopsies were conducted around the tumor site to determine HP status. Patients were then treated with combination 5-FU and cisplatin-based chemotherapy. And we compared chemotherapy response rate and overall survival rate between HP infection group and without HP infection group.

RESULTS

Twelve of 18 patients with HP infection (66.7 %) and 9 of 42 patients without HP infection (21.4 %) showed a partial response to chemotherapy (Chi square P = 0.001). Patients with HP infection had a median survival time of 13 months (95 % CI, 6.9-19.1 months), which was significantly longer than that of patients without HP infection (9 months; P = 0.027, log-rank test).

CONCLUSIONS

Patients with advanced or metastatic gastric cancer with concomitant HP infection had a better response to chemotherapy and had an improved overall prognosis compared with patients without HP infection. Further studies are warranted to confirm these findings.

The relationship between Helicobacter pylori genes cagE and virB11 and gastric cancer

BACKGROUND

The association between Helicobacter pylori gene diversity and gastric cancer has been poorly reported, although it is one of the important ways to explain the gastric pathogenesis. The aim of this study was to investigate the frequency of cagE and virB11 genes in H. pylori isolated from patients with gastric cancer and to analyze the histology profiles.

MATERIALS AND METHODS

The presence of H. pylori and subtypes (cagE and virB11) was detected by PCR from the genomic DNA of 101 patients who had been diagnosed with gastric cancer. The cases were grouped according to the presence/absence of the genes studied and were analyzed in relation to histopathological parameters.

RESULTS

H. pylori infection was detected in 94 out of 101 (93.1%) gastric carcinomas. The cases were categorized into the following groups: cagE+/virB11+, cagE+/virB11-, cagE-/virB11+, and cagE-/virB11-. Frequencies were: 50% (47/94) cagE+/virB11+, 3.2% (3/94) cagE+/virB11-, 10.6% (10/94) cagE-/virB11+, and 36.2% (34/94) cagE-/virB11-. Tumors in the gastric antrum were predominant. An exception was the cagE-/virB11- group, in which tumors had a tendency to be located in the gastric cardia; the majority of the cardia tumors (56% (14/25)) were in this group. Intestinal histology type was the most frequent, but the cagE+/virB11- group only had diffuse tumors. H. pyloricagE+/virB11+ occurred most frequently (except at stage III), and was present at all gastric cancer stages.

CONCLUSIONS

This study is the first to include a relevant number of gastric cancer cases with H. pylori infection, reporting the frequency and relationship of cagE and virB11 genes and the genesis of this tumor. The presence of these cag pathogenicity island genes shows that they are important factors for the pathogenesis and malignancy of gastric cancer related to H. pylori.

Helicobacter pylori em crianças e associação de cepas CagA na transmissão mãe-filho na Amazônia brasileira

Investigou-se a prevalência de infecção pela Helicobacter pylori em amostras de sangue de 100 crianças de 1 a 12 anos e de suas mães através dos métodos de hemaglutinação indireta e anti-CagA pelo ensaio ELISA. Destas 100 crianças, foram obtidas 79 amostras de fezes e realizada pesquisa de antígenos da bactéria nas fezes por ELISA de captura. Os antígenos foram detectados em 54,4% (43/79) das crianças, e os anticorpos no soro em 43% (34/79), métodos que apresentaram desempenhos semelhantes, com maiores discordâncias nas crianças de 1 a 4 anos. A soroprevalência nas crianças foi de 50% (50/100) e nas mães de 86% (86/100). Mães infectadas representaram fator de risco 19 vezes superior ao de mães soronegativas para determinar infecção em seus filhos (p < 0,05), sobretudo as mães com cepas CagA+ (p < 0,05). O contato direto pessoa-pessoa pode ser um modo de transmissão desta infecção.

Detection of the drug-resistant gene of Helicobacter pylori

Antibiotic-resistant Helicobacter pylori (H. pylori) and the resistance rate are increased due to the wide use of antibiotics. At present, the detection of antibiotic-resistant H. pylori is focused on the clarithromycin and metronidazole resistance testing using PCR-based molecular biology techniques. However, PCR-restriction fragment length polymorphism and real-time PCR in combination with melting curve analysis techniques have a broad prospect in detecting drug-resistant clarithromycin. They can detect it from tissue biopsy and stool samples, and thus can be used in detecting the resistance of a wide range of antibiotics. Western blot and PCR- restriction fragment length polymorphism can also detect the resistance of metronidazole, and can therefore develop into the routine procedures for detecting drug-resistant H. pylori.

H pylori (CagA) and Epstein-Barr virus infection in gastric carcinomas: Correlation with p53 mutation and c-Myc, Bcl-2 and Bax expression

AIM: To investigate the interrelationship between H pylori and Epstein-Barr virus (EBV) infection in the gastric carcinogenesis having in focus the p53 mutation and the c-Myc, Bcl-2 and Bax expression.

METHODS: seventy-one gastric carcinoma tissues were assessed by polymerase chain reaction (PCR) for H pylori and in situ hybridization for EBV. c-Myc, Bcl-2 and Bax expression were detected by immunohistochemistry and single-stranded conformational polymorphism (SSCP) for p53 mutation.

RESULTS: The positivity rates for H pylori and EBV were 94.4% and 8.45%, respectively. The majority of the cases displayed only the H pylori presence. All EBV positive cases were also H pylori positive. None infectious agent was observed in 5.55% of the cases. The intestinal type tumor was more frequent in the co-infected and non-infected groups. The female predominated in the non-infected group showing statistical significance (70.4% vs 29.6%, P = 0.039). The Bcl-2 was only detected in the group exclusively infected by H pylori. However, c-Myc and Bax were detected in the three groups but with a low frequency in the co-infected group. Mutation of p53 was present in all groups, with the highest frequencies in the H pylori positive groups.

CONCLUSION: The frequency of H pylori infection in gastric carcinomas was high. The presented data indicated that gastric carcinogenesis has different pathways depending of the presence of the two investigated infectious agents, suggesting a possible involvement of H pylori with apoptotic process. The low expression of c-Myc and Bax in the EBV-positive groups suggests that EBV may inhibit the expression of these proteins. Nevertheless, p53 mutation shows to be a relevant alteration, independent of both infectious agents.