Common soil bacteria that were injected into solid cancers in dogs and one human shrank many of the tumors, scientists reported on Wednesday.
The preliminary findings offer hope that the experimental treatment could turn out to be more effective than existing cancer therapies for some inoperable tumors such as those of the lung, breast and pancreas, which often fail to respond to radiation and chemotherapy.
Radiation requires oxygen to kill cells, but the deep interior of tumors is nearly oxygen-free. Chemotherapy requires blood vessels to carry drugs into tumors, whose interiors generally lack such plumbing.