A common bacteria found in dairy foods and on green vegetables may help treat cervical cancer, a new study suggests. The germ--called Listeria--is the active ingredient in a new vaccine known as Lovaxin C. Researchers say that Listeria attacks tumors in many ways, but it is also easily cleared from the system with antibiotics. In the study of 15 women, seven patients had a stable disease by the study's end, and three of the seven women showed tumor reductions of about 20 percent.