Esophageal cancer: a new risk factor
Bacteria that cause gum disease are linked to esophageal cancer
Klara Galieva, Medical Insider based on University of Louisville: Findings represent the first direct evidence that P. gingivalis could be a risk factor for esophageal cancer
In a new study, scientists suggest that Porphyromonas gingivalis, the bacteria that cause gum disease, is a risk factor for esophageal cancer. The researchers published their findings in the scientific journal Infectious Agents and Cancer (Gao S. et al. Presence of Porphyromonas gingivalis in esophagus and its association with the clinicopathological characteristics and survival in patients with esophageal cancer, in the public domain).
The esophageal mucosa consists of two types of cells, so there are two types of esophageal cancer: adenocarcinoma and squamous cell carcinoma of the esophagus. The development of esophageal cancer is influenced by chemicals, diet, heredity and age. All these factors are common to many other cancers. Cancer is difficult to diagnose in the early stages. In many patients, it develops rapidly after diagnosis and has an unfavorable prognosis. The risk of developing esophageal cancer increases with age. Less than 15% of cases occur in people under 55 years of age. The disease is three to four times more common in men than in women.
The study involved 100 patients with esophageal cancer and 30 people from the control group. The researchers tested samples taken from three types of esophageal tissue: from cancerous tissue, from tissues adjacent to the tumor, and from normal tissue.
The scientists found that R. gingivalis was present in 61% of the cancer tissue samples and only 12% in adjacent tissues. There were no bacteria in the healthy tissue samples.
Study author Huizhi Wang says: "These results prove that infection can become a new risk factor for esophageal cancer, and can also serve as a predictive biomarker for this type of cancer."
He notes that if these data are confirmed, it may mean that the destruction of bacteria in the oral cavity can reduce the number of people with esophageal cancer.
To detect P. gingivalis in tissue samples, the researchers measured the expression of Lys-gingipain, a unique enzyme of this bacterium. They also looked for traces of bacterial cell DNA. Scientists have found that the levels of the enzyme and DNA of bacteria in the cancer tissue of patients are significantly higher than in the surrounding or normal tissue.
This means that either cancer cells are a "preferred niche" for bacteria, or bacteria somehow stimulate the development of cancer. If the reason is that cancer cells offer bacteria a niche, then simple antibiotics can help in the treatment. Another approach could use genetic technology for bacteria and eventually eliminate cancer cells.
Further research should show whether P. gingivalis actually causes esophageal cancer.
"In this case, improving oral hygiene can reduce the risk of cancer, and antibiotics or other antibacterial treatments can prevent the progression of esophageal cancer," says Professor Wang.
The authors of another study stated that gum inflammation can cause diseases of the cardiovascular system.
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04.03.2015