In Japan & Iran with high gastric cancer, h pylori caused chronic & corpus gastritis while India & UAE with low gastric cancer it’s antral gastritis

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In Japan & Iran with high gastric cancer, h pylori ASSOCIATED WITH chronic & corpus gastritis while India & UAE with low gastric cancer it’s antral PREDOMINANT gastritis​

 

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Background/Aim:​

Helicobacter pylori (H. pylori) infection causes peptic ulceration and gastric adenocarcinoma. In Iraq, gastric cancer is rare. We investigated whether infected adults had the antral-predominant pattern of H. pylori-associated gastritis, which does not predispose to cancer.

Materials and Methods:​

We evaluated histopathological changes by the Sydney scoring system in gastric biopsies taken from 30 H. pylori-infected adults and studied the correlation of these changes with the virulence factors. The Mann-Whitney test was used for the comparison of histopathological data. The presence or absence of each pathological index was evaluated with respect to the possession of virulence factors by the infecting H. pylori strain using the χ2 test.

 

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Results:​

Gastric lymphocyte infiltration was more prominent in the antrum (P = 0.01). Neutrophil infiltration was mild and gastric mucosal atrophy was rare. No relationship was found between virulence factors and histopathological changes.

Conclusions:​

The mild pathology and antral-predominant gastritis help explain the low cancer rate in Iraq.

 

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Helicobacter pylori infection causes peptic ulceration and gastric adenocarcinoma. In Iraq, despite the early acquisition of H. pylori infection,[1] gastric cancer is unusually rare.[2] Despite the geographical proximity of Iraq, Turkey and Iran, the incidence of gastric cancer differs hugely among these countries, being ≤ 5/105, 8.9–14.1/105and 38–69/105, respectively.[2] Virulence factors of Iraqi H. pylori strains appear more closely related to Western countries and unlikely to explain the low cancer rate completely.[3] Nothing is known about the distribution of H. pylori- associated inflammation in Iraqi patients or its severity. Thus, we now aim to assess the degree and distribution of inflammation in the stomachs of Iraqi people and the relationship between H. pylori virulence factors (vacA, cagA and dupA) and histopathological changes.

 

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The virulence factors of Iraqi H. pyloristrains and their relationship with clinical outcome were studied previously.[3] In this study, we aimed to explore the relationship between individual virulence determinants and gastric histopathological changes in the gastric antrum and corpus. 66.6% (20/30) and 30% (9/30) of Iraqi strains typed positive for cagA and dupA, respectively. The distribution of vacA allelic types among H. pylori strains is shown in Table 2. For the vacA s, i and m regions individually, 28/30 (93.3%) isolates were the type s1, 8/30 (26.6%) isolates were the type i1 and 15/30 (23.3%) isolates were the type m1. To test whether the presence of specific genotype correlated with histopathological changes in the antrum and the corpus, our data were restratified according to the histological changes. No significant associations were found between vacA, cagA and dupA and histopathological scoring.

 

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DISCUSSION​

H. pylori is a risk factor for gastric cancer and gastric lymphoma.[5] Around the world, despite the high frequency of H. pylori infection, the incidence of gastric cancer is discordant.[5] The annual incidence rate of gastric cancer is very high in Japan and China, but H. pylori seropositivity is low.[5] In contrast, in India, seropositivity of H. pylori is very high but the annual incidence of gastric cancer is low.[5] One possible explanation is the difference in the gastritis pattern as pangastritis and corpus-predominant gastritis are associated with an increased risk of gastric mucosal atrophy and increased risk of cancer.[6,7] In two studies conducted in Japan and Iran, where there is a high gastric cancer rate, it was shown that H. pylori infection was strongly associated with chronic gastritis and that histological corpus gastritis was found with a high frequency.[8,9] On the other hand, in India and UAE, where the gastric cancer rate is low, the distribution pattern of gastritis was found to be antral-predominant.[10,11] Potentially, the low cancer rate in Iraq could be explained by antral-predominant gastritis being the common pattern and/or by inflammation being mild. In a study conducted in Iran, a neighbouring country to Iraq where the gastric cancer rate is very high,[2] it was found that mononuclear cell infiltration was similar throughout the stomach. On an average, patients had pangastritis.[9] In Iraq, we have shown that there is antral-predominant mononuclear cell infiltration. These findings are in agreement with the results from Kenya, an African country with a very low gastric cancer rate, where there is antral-predominant gastritis with significant discordance in the severity of graded variables between antral and corpus biopsies.[12] Furthermore, in Iran, histological evidence of mucosal atrophy was seen in 39% and 22% of the antral and corpus samples, respectively.[13] In another study conducted in Turkey, it was found that 43% of the H. pylori-infected subjects had atrophic gastritis.[14] In our study, glandular atrophy was found in only one (3%) specimen taken from the antrum and one from the corpus. Thus, despite the early acquisition of H. pylori,[1] the presence of atrophy appears rare in Iraq. We speculate that this antral-predominant gastritis and low glandular atrophy rate in Iraq might contribute to the low cancer rate.