As many have already established, metastatic disease is responsible for 9 out of 10 cancer deaths. While studying the spread of cancer cells throughout the body, recent studies have shown a new factor involved in the process: a bacterium called Fusobacterium nucleatum. This microbe lives in healthy gums and is typically harmless. However, laboratory evidence indicates that F. nucleatum is capable of traveling through the bloodstream and attaching to a sugar molecule on the surface of tumor cells, infecting them. Once attached, it triggers a signaling cascade that leads to the cells migrating. In addition, if oral hygiene is neglected, the bacterium can “go rogue” and cause a myriad of disorders, including: tonsillitis, appendicitis, periodontitis, and even preterm labor.
Hints of F. nucleatum’s role were discerned about 9 years ago in a study about colorectal cancer, wherein the bacterium’s DNA was overrepresented in colon tumor tissue compared to healthy tissue. Dozens of subsequent studies have found that infection present in tumor cells is linked to a poorer prognosis for pancreatic, esophageal, and colorectal cancers. The former two exhibited resistance to chemotherapy while the last one showed metastasis. Said metastasis is triggered by a cytokine storm that the bacterium initiates by infecting the cancer cells. This reaction was originally meant to control the infection, but it backfires by making the cancer problem worse. Similar phenomena may also be observed in breast tumors. In 30 percent of human breast cancer samples, incidences of the bacterium were observed in cells with high amounts of the surface sugar molecules Gal/GalNAc. Subsequent data analysis shows that fusobacterium is not a cause of cancer, but is capable of accelerating disease progress. This is because inflammation is part of the metastatic process and an infection that causes a bigger reaction would make it worse by helping cancer cells become more mobile and invasive. The bright side of all of this is that the microbe’s attraction to surface sugar molecules on a tumor cell’s surface could potentially be exploited by binding the bacterium to cancer drugs and then letting it carry said drug to the malignant target.
With this in mind, researchers have found another potential link in cancer pathology, which can help us further unravel the complexities of this group of diseases. Also, this could be another weakness to exploit while new therapies are being developed. So, in light of this news, I’ll leave a link to the article for those interested in the more detailed version of the story: