Fecal Microbiome Alteration May Be a Potential Marker for Gastric Cancer

Although intestinal microbial dysbiosis was confirmed to be associated with many chronic diseases and health status through complicated interaction with the host, the effect on gastric cancer was less studied. In this study, we sequenced the 16S rRNA and 18S rRNA genes of fecal bacteria and fungi, respectively, in 134 gastric cancer patients and 58 healthy controls matched by age and gender. Propensity score matching (PSM) was adopted for adjusting diet habits and lifestyle, and 44 patients and 44 healthy controls (matching population) were enrolled. Serum antibody toH. pyloriand metabolites of the matching population were detected. The positive rates of antibody toH. pyloribetween the patients and the control group did not reach the statistical difference. LEfSe analysis indicated that bacteria were more stable than fungi when adjusting diet and lifestyle.Veillonella,Megasphaera, andPrevotella 7genus andStreptococcus salivariussubsp.Salivarius,Bifidobacterium dentium, andLactobacillus salivariusspecies in bacteria were related to the risk of gastric cancer and showed a good diagnostic value in distinguishing the patients from healthy controls.Streptococcus mitisshowed a risk effect for gastric cancer; however, the effect turned into be protective after PSM. Serum L-alanine, L-threonine, and methionol were positively associated withVeillonellaandStreptococcusand several fungi genus. Overall, our findings indicated that fecal microbiome constitution alteration may be associated with gastric cancer through influencing the amino acid metabolism.