Japanese arboreal tree
Bacteria present in the intestines of the Japanese tree frog made the tumors disappear completely in experiments with laboratory mice.
Scientists have identified a promising new cancer-fighting strategy hidden in intestinal bacteria of a Japanese tree frogafter experiments demonstrated that a bacterial strain was able to completely eliminate tumors in mice without causing serious side effects.
The research, led by scientists at the Japan Advanced Institute of Science and Technology and the journal Gut Microbes, is based on a long-standing observation that amphibians and reptiles rarely develop cancer. Curious to know whether this resistance could be linked to their microbiomes, scientists investigated whether these animals’ bacteria could suppress tumor growth.
The researchers isolated 45 bacterial strains from the intestinal microbiota of frogs, newts and lizards and tested them in mouse cancer models. Of these, nine showed measurable antitumor effects. One strain stood out dramatically: Ewingella americana, derived from the Japanese tree frog (Dryophytes japonicus).
A single dose of E. americana not only reduced tumors in treated mice, but also made it disappear completely. Even more impressive, when the cancer cells were reintroduced 30 days later, the treated mice did not develop new tumors over the next month, suggesting a long-lasting protective effect.
Further investigation revealed that the bacteria acts through a dual mechanism. Directly attacks tumor tissue while simultaneously strengthens the immune systemincreasing the activity of T cells, B cells and neutrophils, all critical components of the body’s defense against cancer. Researchers believe the bacteria’s effectiveness may derive from its evolution in low-oxygen environments, similar to the conditions found inside solid tumors, where conventional immune responses and chemotherapy drugs often struggle.
Safety results from animal studies were also encouraging. The bacteria were quickly eliminated from the bloodstream of mice, did not cause lasting toxicity and did not damage healthy organs. In direct comparisons, injections of *E. americana* surpassed several existing oncological treatments, including doxorubicin, a commonly used chemotherapy drug, explains .
Despite the promising discoveries, the researchers emphasize that the work is still is at an early stage. Additional studies are needed to determine whether the results can be replicated in humans. Future research will explore the bacteria’s effectiveness against other types of cancer, its performance in conjunction with existing therapies and safer delivery methods.
Safety will be a major concern if the treatment advances to clinical trials, given that *E. American* can cause infections in humans under certain conditions. Scientists will have to determine whether its therapeutic benefits can be harnessed without major risks.
