Fecal Microbiome Alteration May Be a Potential Marker for Gastric Cancer.

Juan Wu,Wei Dong,Chunjie Xiang,Cong Zhang,Junfeng Zhang,Ruimin Tong,Shuo Xu,Liyun Shi,Bin Lu,Yuhao Teng,Ruiping Wang,Dongqing Yang

doi:10.1155/2020/3461315

Abstract

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 to H. pylori and metabolites of the matching population were detected. The positive rates of antibody to H. pylori between 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, and Prevotella 7 genus and Streptococcus salivarius subsp. Salivarius, Bifidobacterium dentium, and Lactobacillus salivarius species in bacteria were related to the risk of gastric cancer and showed a good diagnostic value in distinguishing the patients from healthy controls. Streptococcus mitis showed 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 with Veillonella and Streptococcus and several fungi genus. Overall, our findings indicated that fecal microbiome constitution alteration may be associated with gastric cancer through influencing the amino acid metabolism.

Highlights

Gastric cancer (GC) ranked the third most commonly diagnosed cancer and the second most common cause of cancer death in 2015 in China [1]
The alpha diversities of bacteria and fungi between the GC and control groups were compared both in the original and matching population (i.e., ACE, Chao, Shannon, and Simpson index), and we did not find any difference in the bacteria group
Our results indicated that Lactobacillus salivarius relative abundance was higher in GC cases than in healthy controls, and this tendency is not influenced by environmental factors

Summary

Introduction

Gastric cancer (GC) ranked the third most commonly diagnosed cancer and the second most common cause of cancer death in 2015 in China [1]. H. pylori infection was the only confirmed bacterium in GC and regarded as I carcinogenic factor by IARC [2]. Besides the H. pylori, other bacteria were confirmed to survive in the hostile environment of the stomach [3]. The high infection rate of H. pylori [4] and low incident rate of GC among the infected population may indicate the more complex ecosystem in the stomach. The colon and distal gut have the largest ecosystem in the body (about 1012 per gram of contents), and this ecosystem was regarded as a metabolic organ [6].

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