Association between oral microflora and gastrointestinal tumors (Review)

  • Authors:
    • Xiaoxiao Li
    • Sibo Zhu
    • Tiejun Zhang
    • Xingdong Chen
  • View Affiliations

  • Published online on: June 10, 2021     https://doi.org/10.3892/or.2021.8111
  • Article Number: 160
Metrics: Total Views: 0 (Spandidos Publications: | PMC Statistics: )
Total PDF Downloads: 0 (Spandidos Publications: | PMC Statistics: )


Abstract

The oral cavity contains the highest density and the most species of microorganisms compared with other parts of the body. Recent studies have determined that the species and abundance of oral microflora are closely associated with the development of upper gastrointestinal tumors, including oral, esophageal and gastric cancer. Additionally, differential abundant microbiota in patients with cancer and abnormal microorganisms inside the tumor tissue have been identified as critical markers of tumorigenesis. There is evidence to suggest that certain genera, including Firmicutes, along with various species, such as Porphyromonas, can increase the risk of oral cancer. Furthermore, Porphyromonas gingivalis is a risk factor for esophageal carcinoma, while Helicobacter pylori infections are a main cause of gastric cancer. Currently, as far as carcinogenic mechanisms of oral microorganisms are concerned, it has been hypothesized that the production of carcinogenic substances, chronic inflammation and altered cell metabolisms may be mechanisms by which oral microorganisms influence the development of upper gastrointestinal cancer. Certain phrases, including ‘oral microbes’, ‘oral microorganism’, ‘oral microbiology’, ‘oral microflora’, ‘oral cancer’, ‘oral carcinoma’, ‘carcinoma of mouth’, ‘esophagus cancer’, ‘esophageal cancer’, ‘esophageal carcinoma’, ‘carcinoma of esophagus’, ‘gastric cancer’, ‘gastric carcinoma’, ‘stomach cancer’, ‘cancer of the stomach’, ‘carcinogenic mechanism’ and ‘carcinogenesis’, were searched as key words in PubMed and Web of Science for articles published between 1975 to 2020. A total of 1,512 studies were obtained. After further searching the abstracts for key words, such as oral microorganisms, oral cancer, esophagus cancer, gastric cancer and carcinogenic mechanisms, 137 studies were selected. The current review systematically and comprehensively summarized the association between the oral microbiota and oral, esophageal and gastric cancer. Additionally, the current review described the carcinogenic mechanisms of oral microbes and attempted to identify common molecular mechanisms among different types of tumor. The association between upper gastrointestinal cancer therapy and oral microflora was also assessed. The present review may be used as a reference for future diagnosis and therapeutics for upper gastrointestinal tumors.
View Figures
View References

Related Articles

Journal Cover

August-2021
Volume 46 Issue 2

Print ISSN: 1021-335X
Online ISSN:1791-2431

Sign up for eToc alerts

Recommend to Library

Copy and paste a formatted citation
x
Spandidos Publications style
Li X, Zhu S, Zhang T and Chen X: Association between oral microflora and gastrointestinal tumors (Review). Oncol Rep 46: 160, 2021
APA
Li, X., Zhu, S., Zhang, T., & Chen, X. (2021). Association between oral microflora and gastrointestinal tumors (Review). Oncology Reports, 46, 160. https://doi.org/10.3892/or.2021.8111
MLA
Li, X., Zhu, S., Zhang, T., Chen, X."Association between oral microflora and gastrointestinal tumors (Review)". Oncology Reports 46.2 (2021): 160.
Chicago
Li, X., Zhu, S., Zhang, T., Chen, X."Association between oral microflora and gastrointestinal tumors (Review)". Oncology Reports 46, no. 2 (2021): 160. https://doi.org/10.3892/or.2021.8111