Doctors try 'natural killer cells' on liver cancer

The Miami HeraldDecember 10, 2010 

They're called "natural killer cells" but they're a part of the human immune system that helps save lives. Now doctors from Miami and Japan have developed new ways to pump up the cells to attack cancer even more aggressively.

Encarnacion Miranda, a 58-year-old car salesman from Key Largo, is counting on the cells -- which exist in healthy livers -- to save his life. He's the first patient in a clinical trial at the University of Miami of 25 liver patients seeking Food and Drug Administration approval of the new treatment.

``It's scary,'' Miranda said Thursday, during an announcement of the medical trial. ``But I feel really good.''

Miranda's liver had been dogging him since 1979, when he contracted hepatitis C from a blood transfusion. By October 2009, chronic exhaustion forced him to give up his favorite sport, fishing for yellowtail snapper in the Florida Keys. That's when he learned his hepatitis had become liver cancer.

Doctors gave Miranda a liver transplant. But, knowing that liver cancer recurs in up to 20 percent of cases due to tumor cells left hiding in the body, they went further. Before the transplant, they took blood from the donated liver, extracted the natural killer immune cells from it, then cultured and expanded them in laboratory flasks for four days to increase their power against any remaining cancer cells. They fed them intravenously back into Miranda's new liver.

Doctors say the killer cells, which recognize cancer cells as alien and try to destroy them, also will help fight any remaining hepatitis C. They aren't sure yet whether their findings on natural killer cell expansion might be broadened to work in other organs and combat other cancers.

The procedure was studied for four years at the University of Hiroshima. Dr. Masahiro Ohira performed the procedure on 24 patients; 22 survived cancer-free for more than three years. It cut in half the recurrence of cancer.

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