A Bacterium From a Japanese Frog's Gut Completely Destroyed Cancer Tumors

About this work

Japanese researchers at JAIST tested 45 bacterial strains from the guts of frogs, newts, and lizards on mice with colorectal cancer — chasing a simple question: why do amphibians almost never get cancer? One strain, Ewingella americana from a tree frog's intestines, delivered a result that made the team double-check their data — a 100% complete tumor elimination rate after a single dose, outperforming standard chemotherapy and immunotherapy. The bacterium attacks the tumor from two directions at once: it colonizes the oxygen-starved core of the tumor that conventional drugs struggle to reach, while simultaneously mobilizing the body's own immune system. When researchers re-injected the same cancer cells into cured mice a month later, the cancer didn't return — pointing to a lasting immune memory against it. The article breaks down the mechanism in detail, gives an honest look at the study's limitations (this is mice, not humans; one cancer type; years likely stand between this and human trials), and reflects on why some of the strongest scientific breakthroughs come not from advanced technology, but from asking a careful question about something nature had already solved on its own. Source: Miyako E. et al., Gut Microbes, JAIST, July 2026.