An oral bacteria discovered by researchers may be linked to colorectal cancer development and progression. Elevated levels of a Fusobacterium nucleatum subtype were found in half of examined tumors in a study published in Nature.
By examining tumors from 200 patients, the researchers observed elevated levels of a Fusobacterium nucleatum (Fn) subtype in half of the cases compared with healthy tissue. This microbe was also more prevalent in the stool samples of colorectal cancer patients compared with healthy patients.
Susan Bullman, Ph.D., and Christopher D. Johnston, Ph.D., led the study, noting colorectal tumors containing the bacterium subtype correlated with poor survival rates and prognosis. The research marks a pivotal step towards understanding the microbiological factors contributing to colorectal cancer's aggressiveness, they noted.
What was thought to be a single Fusobacterium nucleatum subspecies within colorectal tumors actually consists of two distinct lineages, or "clades." This revelation, akin to discovering the Rosetta Stone, provides a nuanced understanding of the bacterium's behavior and its influence on tumor development, noted the investigators.
They identified 195 genetic differences between the clades, with the tumor infiltrating Fn subspecies animalis (Fna) C2 type showing unique genetic traits that enable it to withstand stomach acid and thrive in the lower gastrointestinal tract. This specificity suggests targeting the Fna C2 subtype could lead to more effective colorectal cancer screening and treatment options.
This study not only advances our understanding of the microbiome's role in cancer but also opens new doors for developing microbial cellular therapies, noted investigators. These therapies could use modified bacterial strains to deliver treatment directly to tumors, offering a novel and promising approach to combating colorectal cancer.
The research was supported by the National Institute of Dental and Craniofacial Research, the National Cancer Institute, the W.M. Keck Research Foundation, and a Washington Research Foundation Fellowship. Some of the investigators disclosed relationships with health care and pharmaceutical companies.
