Helicobacter pylori causes diseases ranging from gastritis to peptic ulcer disease to gastric cancer. Geographically, areas with high incidences of H. pylori infection often overlap with areas with high incidences of gastric cancer, which remains one of the leading causes of cancer-related deaths worldwide. Strains of H. pylori that carry the virulence factor cytotoxin-associated gene A (cagA) are much more likely to be associated with the development of gastric cancer. Moreover, particular C-terminal polymorphisms in CagA vary by geography and have been suggested to influence disease development. We conducted a large-scale molecular epidemiologic analysis of South Korean strains and herein report a statistical link between the East Asian CagA EPIYA-ABD genotype and the development of gastric cancer. Characterization of a subset of the Korean isolates showed that all strains from cancer patients expressed and delivered phosphorylatable CagA to host cells, whereas the presence of the cagA gene did not strictly correlate to expression and delivery of CagA in all noncancer strains.

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These findings suggest that EGCG may prevent the alveolar bone resorption that occurs in periodontal diseases by inhibiting the expression of MMP-9 in osteoblasts and the formation of osteoclasts.

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Gastritis, peptic ulcer disease, and gastric cancer are a few of the diverse disease manifestations that have been shown to be associated with infection by Helicobacter pylori. Why some individuals develop more severe forms of disease remains largely unknown. In this study, 225 South Korean strains were genotyped for vacA and then analyzed to determine if particular genotypes varied across disease state, sex, or cagA allele. Of these strains, 206 strains carried an s1/i1/m1 allele, 11 strains carried an s1/i1/m2 allele, and 8 strains carried an s1/i2/m2 allele. By using Fisher's exact test, a statistical association between variations in the cagA and vacA alleles was identified (P ‫؍‬ 0.0007), and by using log linear modeling, this variation was shown to affect the severity of disease outcome (P ‫؍‬ 0.027). Additionally, we present evidence that variation within the middle region of VacA contributes significantly to the distribution of vacA alleles across gender (P ‫؍‬ 0.008) as well as the association with disease outcome (P ‫؍‬ 0.011). In this South Korean population, the majority of H. pylori strains carry the vacA s1/i1/m1 allele and the CagA EPIYA-ABD allele. These facts may contribute to the high incidence of gastric maladies, including gastric cancer.

Our findings suggest that metformin may exert a beneficial effect on alveolar bone in periodontitis by increasing osteoblast differentiation.

Using highly sensitive methods relying on 16S ribosomal RNA-based oligonucleotide probes, we confirmed the strong association of 7 putative periodontopathogens with AP patients in a Korean population. With the exceptions of Fusobacterium sp. and B. forsythus, all the periodontopathogens were significantly more associated with the healthy sites of periodontitis subjects than in the healthy sites of periodontally healthy subjects.

We found that South Korean Helicobacter pylori isolates predominantly carry homB at locus B and that there is no association between the homB allele and the cagA allele or the development of gastric cancer within this population. Uniquely, several East Asian strains carried multiple copies of the hom genes.