Holy crap!
Just ran across this.

Using modified HIV cells to kill leukemia cells.

"According to Dr. June, the process includes drawing blood from the patient, and extracting the T-cells, at which point a modified harmless version of HIV was added to the cells, and injected back into the patients in the study. Once back in the body, the modified cells act as “serial killers,” which attacked and destroyed at least 1,000 cancer cells in the 3 test cases."