A therapy that retrains the body's immune system to fight cancer has provoked excitement after more than 90% of terminally ill patients reportedly went into remission.
White blood cells were taken from patients with leukaemia, modified in the lab and then put back.
But the data has not been published or reviewed and two patients are said to have died from an extreme immune response.
Experts said the trial was exciting, but still only "a baby step."
The news bubbled out of the American Association for the Advancement of Science's annual meeting in Washington DC.
The lead scientist, Prof Stanley Riddell from the Fred Hutchinson Cancer Research Centre in Seattle, said all other treatments had failed in these patients and they had only two-to-five months to live.
He told the conference that: "The early data is unprecedented." Read the rest of the story here.
Excitement at new cancer treatment - BBC Video