Researchers from Johns Hopkins University School of Medicine have discovered that a type of bacteria known for causing dental plaque may be contributing to a hard-to-treat form of colorectal cancer. The study, not yet peer-reviewed, found this bacterium, Fusobacterium nucleatum, in 50% of colorectal tumors analyzed, suggesting a new direction for treatment and screening methods.

Colorectal cancer, the second leading cause of cancer deaths in the U.S., has seen an alarming increase in younger people, often diagnosed at more advanced stages. The bacteria, typically found in the mouth, has been long suspected to be linked to cancer growth. This study sheds light on how it might evade the immune system and protect tumor cells from cancer-fighting drugs.

The research analyzed the bacterial composition of nearly 200 colorectal tumors and stool samples from over 1,200 individuals. Findings revealed two distinct subspecies of the bacteria, one of which appears to shield the tumor cells, hindering the effectiveness of chemotherapy and increasing the risk of recurrence.

These insights open new possibilities for targeted therapies, including pre-treatment with antibiotics and the development of new drugs to specifically target this bacterial subtype. The findings also hint at potential new screening methods, like mouth swabs, to identify individuals at higher risk for aggressive colon cancer. This research emphasizes the significant role of the human microbiome in cancer risk and development, marking a crucial advancement in cancer research.