Diseases come from the mouth, oral microbes are closely related to esophageal cancer

INTRODUCTION In recent years, numerous studies have reported a possible association between oral microbes and increased risk of gastrointestinal tumors
.

Recently, Wang Tianhu's team from the Third Affiliated Hospital of Chongqing Medical University conducted a study on the characteristics of oral microbiota in Chinese patients with esophageal cancer
.

They plan to create a database of oral microbes associated with esophageal cancer in China to pave the way for future research
.

The research has been published in BioMed Research International
.

BackgroundEsophageal cancer is one of the most common cancers of the upper gastrointestinal tract.
It is currently the ninth most common cancer in the world and the sixth leading cause of cancer death in the world.
It is most common in men
.

However, esophageal cancer is often not diagnosed early due to the lack of relevant biomarkers, and even few biomarkers are available when designing treatment regimens for patients with advanced esophageal cancer
.

Recent studies have found associations between the oral microbiome and disease, including systemic disease and cancer
.

The oral microbiota is almost identical to the esophageal microbiota, and changes in the oral microbiota can directly affect the esophagus
.

Therefore, this study attempted to explore the relationship between the oral microbiome and esophageal cancer in Asians, and to create a related oral microbiome database
.

Collected saliva samples were studied by microbial 16S rDNA sequencing technology to compare the differences in the salivary microbiome between patients with esophageal cancer and controls
.

Research Methods The cases used in this study were 33 patients who were examined and diagnosed with esophageal squamous cell carcinoma in the Third Affiliated Hospital of Chongqing Medical University from July 2019 to September 2020, and the control group was 35 patients who received physical examination in the local area.
There were no significant differences in age, gender or body mass index between the two groups
.

The saliva secreted by the subjects was collected from 8:30 am to 11:30 am, and the microbial DNA was extracted, sequenced and statistically analyzed
.

Main results All saliva samples were sequenced and found no significant differences in alpha-diversity between the esophageal cancer group and the control group
.

The Shannon indices were 3.
86 and 3.
91, respectively (p=0:61; Figure 1(a))
.

The Simpson indices were 0.
053 and 0.
049, respectively (p=0:62; Fig.
1(b))
.

Significant statistical differences were found between the esophageal cancer group and the control group in the β-diversity analysis, indicating a comparative difference in the abundance of microbiota in the saliva of the esophageal cancer group and the control group (Fig.
2)
.

At the phylum level, Firmicutes and Bacteroidetes were more abundant in the esophageal cancer group than in the control group, while Proteobacteria were less abundant
.

At the genus level, the esophageal cancer group had more Streptococcus and Prevotella and less Neisseria (Figure 3).
Bacterial differences between the two groups were identified in the Mann-Whitney U test, Planktonic bacteria and Verrucobacterium were found in the esophageal cancer group, but not in the control group
.

At the genus level, capnophagocytic bacteria in the esophageal cancer group were significantly higher than those in the control group
.

At the family level, the control group was dominated by Lachnospiraceae (Fig.
4)
.

Based on the above analysis, using the method of linear discriminant analysis, at all taxonomic levels, ten genera with higher abundance were identified in the healthy control group and ten genera with significant differences were identified in the esophageal cancer group (Fig.
5).
)
.

Combined with other research findings, Prevotella may be associated with the development of esophageal cancer; lower levels of Neisseria may increase the risk of esophageal cancer; higher concentrations of carbon dioxide-phagocytic bacteria in the mouth are promising as biological predictors of esophageal cancer markers, but these depend on future research
.

Conclusions The current study identified a direct relationship between esophageal cancer and different oral microbiota, and by building a database, predicted the function of different oral microbiota
.

Reference: Characteristics of Oral Microbiota in Patients with Esophageal Cancer in China.
Biomed Res Int.
2021 Dec 16;2021:2259093.
doi: 10.
1155/2021/2259093.
eCollection 2021.