Link found between oral bacteria and bowel cancer
Researchers from Ireland, the UK and the US have found a correlation between the presence of a particular type of oral bacteria found in tumours and the spread of bowel cancer.
Colorectal cancer (bowel cancer in a broader sense) has one of the highest morbidity and mortality rates among other oncopathologies: ten per cent of newly diagnosed cases of cancer are attributable to it. Previously, researchers have shown that the state of the intestinal microbiome - a set of all microorganisms colonising the biotope - plays a key role in the development of tumours.
The authors of the paper - scientists from the Royal College of Surgeons in Ireland, the School of Medicine, Dentistry and Biomedical Sciences at Queen's University in Belfast (UK) and the Fred Hutchinson Cancer Research Center in Seattle (Washington, USA) - found that the bacteria Fusobacterium nucleatum are more prevalent in tumour tissue compared to the adjacent mucosa. Their findings are presented in a paper published in the journal Gut.
Fusobacterium nucleatum is a fusobacterium that predominates among the other hundreds of species of plaque bacteria. Together with Prevotella intermedia, Parvimonas micra make up the "orange" periodontal microbial complex.
The scientists analysed samples from 140 Northern Ireland residents with stage two to three cancer and 605 patients from the Cancer Genome Atlas, an international project that systematises data on genetic mutations that lead to cancer. Fusobacterium load was determined by real-time PCR after tumour resection. In the end, Fusobacterium nucleatum was detected in 101 of 140 (72 per cent) people in the first group and 558 of 605 (92 per cent) participants in the second group.
Fusobacteria were found to be linked to colorectal cancer pathogenesis, progression and response to treatment: they infected tumours, changing the behaviour of their cells and providing a pathway to spread to other organs.
"We observed a more specific prevalence of Fusobacteriales in patients with microsatellite unstable tumours. High levels of Fusobacteriales were associated with poor prognosis specifically in a subgroup of patients with mesenchymal tumours, but not with other molecular subtypes," the researchers wrote.
According to the scientists, a single approach to the treatment of cancer patients with Fusobacteriales and can not be, although the use of antibiotics in vivo slowed the growth of neoplasms. It is worth remembering that the use of such drugs by patients with Fusobacteriales-infected tumours is limited because Fusobacteriales penetrate deep into tumour, immune and endothelial cells, where they adapt and persist. In addition, long-term antibiotics are fraught with intestinal dysbiosis - this can affect the development and outcome of the disease. Therefore, the authors of the study recommend that doctors give patients the opportunity to be screened for oral bacteria and molecular subtyping of tumours in order to diagnose such conditions in time.