What we know so far: Scientists have uncovered a naturally occurring gut bacterium from common tree frogs that can completely eradicate cancerous tumors in lab animals. The organism even outperforms some existing therapies. The discovery has the potential to revolutionize cancer treatment, but the research needs more work.
Japanese researchers have identified a naturally occurring bacterium that shows promise as a treatment for a specific type of cancer. In a study published in the journal Gut Microbes, a team led by Professor Eijiro Miyako at the Japan Advanced Institute of Science and Technology reported that Ewingella americana, isolated from the gut of a common tree frog, demonstrated a strong ability to destroy cancer cells in laboratory testing.
To reach that conclusion, the researchers examined 45 different bacterial strains found in the intestines of Japanese tree frogs, Japanese fire-bellied newts, and Japanese grass lizards. After an initial screening, they narrowed the field to nine strains that showed measurable antitumoral effects.
Among those candidates, E. americana stood out. In experiments involving lab mice injected with colorectal cancer, the bacterium completely eradicated the tumors, achieving a 100 percent response rate. The results exceeded those produced by existing treatment models, including antibody-based inhibitors and chemotherapy.
The research shows that E. americana destroys cancer cells through multiple complementary mechanisms. Medical Xpress notes that the anaerobic bacterium has a direct cytotoxic effect by accumulating inside oxygen-deprived cancer cells, increasing its presence by roughly 3,000 times after a single intravenous administration.
The bacterium both overstimulates the immune system and selectively targets cancer cells. At the tumor site, its rapid proliferation releases inflammatory proteins that draw T cells, B cells, and other immune cells, concentrating the body's defenses where they are most needed. It then accumulates in tumors while leaving healthy organs unaffected, likely due to the anaerobic environment of cancerous tissue, weakened local immune suppression, and the distinct metabolic conditions of tumors.
The study notes that E. americana appears safe for administration, as it rapidly clears from the bloodstream and shows no tendency to colonize healthy tissues. The bacterium can trigger a mild inflammatory response, which typically subsides within 72 hours.
Miyako's team is developing a cancer therapy based on the naturally occurring bacterium and continuing research to better understand this new ally in the fight against cancer. They are particularly focused on how E. americana affects other types of cancer, optimizing administration to reduce inflammatory side effects, and exploring how it can work alongside existing immunotherapy and chemotherapy treatments.
Scientists discover an amphibian gut bacterium 100% effective in destroying cancer cells in rats
