Oral Bacteria Linked to Esophageal Cancer



Porphyromonas gingivalis, the bacteria responsible for gum disease, is present in 61% of patients with esophageal squamous cell carcinoma (ESCC). According to researchers at the University of Louisville School of Dentistry, the bacteria also was found in 12% of tissues adjacent to the cancerous cells, while it was undetected in normal esophageal tissue.

“These findings provide the first direct evidence that P gingivalis infection could be a novel risk factor for ESCC 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 school of dentistry.

About 15,000 people in the United States are diagnosed with esophageal cancer each year, according to the Centers for Disease Control and Prevention. Early diagnosis is difficult, and the disease is characterized by rapid progression and high mortality.

“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 ESCC,” said Wang.

The researchers tested tissue samples from 100 patients with ESCC and 30 normal controls. Then, they 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.

The bacteria-distinguishing enzyme and its DNA were significantly higher in the cancerous tissue of ESCC patients than in surrounding tissue or normal control sites. The bacteria’s presence also correlated with other factors such as cancer cell differentiation, metastasis, and overall survival rate.

Wang notes that there are two likely explanations. First, ESCC cells may be a preferred niche for P gingivalis to thrive. Or, the infection of P gingivalis facilitates the development of esophageal cancer. If ESCC cells are a preferred niche, simple antibiotics may be useful in treating caner. Or, researchers can develop other therapeutic approaches using genetic technology to target the bacteria and destroy the cancer cells.

“Should P gingivalis prove to cause ESCC, the implications are enormous,” said Wang. “It would suggest that improving oral hygiene may reduce ESCC risk; screening for P gingivalis in dental plaque may identify susceptible subjects; and using antibiotics or other anti-bacterial strategies may prevent ESCC progression.”

The study, “Presence of Porphyromonas Gingivalis in Esophagus and Its Association with the Clinicopathological Characteristics and Survival in Patients with Esophageal Cancer,” was published by Infectious Agents and Cancer.

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