Researchers Find Possible Association Between Oral Bacteria and Esophageal Cancer

Key Points

  • The expression of lysine-gingipain, an enzyme unique to P gingivalis, as well as the presence of the bacterial cell DNA were measured within the esophageal tissues. Both the bacteria-distinguishing enzyme and its DNA were significantly higher in the cancerous tissue of patients with esophageal squamous cell carcinoma than in surrounding tissue or normal control sites.
  • Researchers only detected P gingivalis in 12% of tissues adjacent to the cancerous cells, while this organism was undetected in normal esophageal tissue.
  • The presence of P gingivalis also correlated with other factors, including cancer cell differentiation, metastasis, and overall survival rate.

University of Louisville School of Dentistry researchers have found that a bacterial species responsible for gum disease, Porphyromonas gingivalis, is present in 61% of patients with esophageal squamous cell carcinoma. The findings, published by Gao et al in Infectious Agents and Cancer, only detected P gingivalis in 12% of tissues adjacent to the cancerous cells, whereas this organism was undetected in normal esophageal tissue.

“These findings provide the first direct evidence that P gingivalis infection could be a novel risk factor for [esophageal squamous cell carcinoma], and may also serve as a prognostic biomarker for this type of cancer,” said Huizhi Wang, MD, PhD, Assistant Professor of Oral Immunology and Infectious Diseases at the University of Louisville School of Dentistry. “These data, if confirmed, indicate that eradication of a common oral pathogen may contribute to a reduction in the significant number of people suffering with [esophageal squamous cell carcinoma].”

In collaboration with the College of Clinical Medicine of Henan University of Science and Technology in Luoyang, China, Dr. Wang and his colleagues tested tissue samples from 100 patients with esophageal squamous cell carcinoma and 30 normal controls.

Study Findings

The research team measured the expression of lysine-gingipain, an enzyme unique to P gingivalis, as well as the presence of the bacterial cell DNA within the esophageal tissues. Both the bacteria-distinguishing enzyme and its DNA were significantly higher in the cancerous tissue of patients with esophageal squamous cell carcinoma than in surrounding tissue or normal control sites. The researchers also found the presence of P gingivalis correlated with other factors, including cancer cell differentiation, metastasis, and overall survival rate.

According to Dr. Wang, there are two likely explanations: either esophageal squamous cell carcinoma cells are a preferred niche for P gingivalis to thrive, or the infection of P gingivalis facilitates the development of esophageal cancer.

If the former is true, Dr. Wang said simple antibiotics may prove useful, or researchers can develop other therapeutic approaches for esophageal cancer utilizing genetic technology to target the P gingivalis and ultimately destroy the cancer cells.

“Should P gingivalis prove to cause [esophageal squamous cell carcinoma], the implications are enormous,” Dr. Wang said. “It would suggest that improving oral hygiene may reduce [esophageal squamous cell carcinoma] risk; screening for P gingivalis in dental plaque may identify susceptible subjects; and using antibiotics or other antibacterial strategies may prevent [esophageal squamous cell carcinoma] progression.”

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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