Madhawa Gunathilake

Although the microbiome has a potential role in gastric cancer (GC), little is known about microbial dysbiosis and its functions. This study aimed to observe the associations between the alterations in gastric microbial communities and GC risk. The study participants included 268 GC patients and 288 controls. The 16S rRNA gene sequencing was performed to characterize the microbiome. Streptococcus_NCVM and Prevotella melaninogenica species were highly enriched in cases and controls, respectively. Those who were in the third tertile of P. melaninogenica showed a significantly decreased risk of GC in total (odds ratio (OR): 0.91, 95% confidence interval (CI): 0.38–0.96, p-trend = 0.071). Class Bacilli was phylogenetically enriched in cases, while phylum Actinobacteria, class Actinobacteria were related to the controls. The microbial dysbiosis index (MDI) was significantly higher for the cases compared with the healthy controls in the female population (p = 0.002). Females in the third tertile of the MDI showed a significantly increased risk of GC (OR: 2.66, 95% CI: 1.19-5.99, p-trend = 0.017). Secondary bile acid synthesis and biosynthesis of ansamycins pathways were highly abundant in cases and controls, respectively. Dysbiosis of gastric microbial communities is associated with an increased risk of GC specifically in females.

Gaussian graphical models (GGMs) are novel approaches to deriving dietary patterns that assess how foods are consumed in relation to one another. We aimed to apply GGMs to identify dietary patterns and to investigate the associations between dietary patterns and gastric cancer (GC) risk in a Korean population. In this case-control study of 415 GC cases and 830 controls, food intake was assessed using a 106-item semiquantitative food frequency questionnaire that captured 33 food groups. The dietary pattern networks corresponding to the total population contained a main network and four subnetworks. For the vegetable and seafood network, those who were in the highest tertile of the network-specific score showed a significantly reduced risk of GC both in the total population (OR = 0.66, 95% CI = 0.47–0.93, p for trend = 0.018) and in males (OR = 0.55, 95% CI = 0.34–0.89, p for trend = 0.012). Most importantly, the fruit pattern network was inversely associated with the risk of GC for the highest tertile (OR = 0.56, 95% CI = 0.38–0.81, p for trend = 0.002). The identified vegetable and seafood network and the fruit network showed a protective effect against GC development in Koreans.

Although physical activity (PA) is beneficial for prolonging lifespan, evidence for the protective role of PA against the development of gastric cancer (GC) is not yet well established. This study assessed the association between PA and GC risk in patients with and without Helicobacter pylori (H. pylori) infection in a Korean population. In total, 415 GC patients and 830 controls were enrolled at the National Cancer Center, Korea. The International Physical Activity Questionnaire-Short Form was used to collect PA data. The odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using unconditional logistic regression models. In the H. pylori-positive group, subjects who engaged in regular exercise showed a significantly reduced risk of GC in the entire population (OR = 0.52, 95% CI = 0.38–0.70) and in females (OR = 0.60, 95% CI = 0.21–0.64). Subjects who engaged in a high level of total PA showed a significantly reduced risk of GC relative to subjects in the lowest tertile in the fully adjusted model (OR = 0.46, 95% CI = 0.32–0.65, p-trend < 0.001). There was an inverse association between PA and GC risk in the entire population, and in the H. pylori-positive subgroup. Our data indicate the need for the promotion of all domains of PA, especially for Korean populations.