This works in mice with small tumors for two weeks until the experiment ends. It's quite different form working in humans with big tumors for 5 years.

Mice are good for early tries. The researchers had 9 bacterias and only 1 was successful. Experiments in mice are cheaper and have less ethical problems than experiments in humans.

(Hey! They even injected the cancer cells in mice and waited a week until it grow. Nobody will approve that in humans.)