21.   Researchers are experimenting with using cancer to fight cancer, injecting reprogrammed cells into otherwise untreatable tumors.

22.   Scientists injected the cells into the tails of rats that had suffered heart attacks.

23.   Scientists at the Complutense and Autonoma universities in Madrid, Spain, injected glioma cells into the brains of rats to produce tumors.

24.   The cells were then injected into the scar tissue that formed in the damaged zone of the heart muscle.

25.   The engineered cells were then injected into the muscles of mice that are diabetic and normally develop high levels of glucose in the blood.

26.   The modified cells were then injected into the forebrain of four of the monkeys.

27.   They injected glioma cells into the brains of rats to produce tumors.

28.   These cells were injected into mice.

29.   They injected the cells into the blood stream of a second group of mice whose bone marrow had been killed with radiation.

30.   Unaltered cancer cells were injected into other mice.