In a major breakthrough in the search for a cure for cancer, the first human trials are to begin using a technique that has already been shown to destroy the disease in mice. The trials are the culmination of years of research prompted by the discovery of a cancer-proof mouse by researchers almost a decade ago. More than 20 cancer patients will be given white blood cells with cancer-killing properties in an attempt to boost their immune system's fight against the deadly illness. The work stems from experiments into the metabolism of a humble laboratory mouse whose immunity to cancer defied the repeated attempts of scientists to kill it with high-level doses of cancer cells. White blood cells taken from the animal and its offspring were subsequently used to cure other mice of advanced cancers. The white blood cells destroyed the cancer cells but left normal cells alone. This discovery encouraged scientists to study how people might be helped to fight off cancer by being given a boost of white blood cells called granulocytes. Laboratory tests have since shown how human granulocytes can destroy cervical, prostate and breast cancer cells, provided sufficient numbers of cancer-killing granulocytes from healthy donors are used. Scientists are now confident that the treatment will prove just as successful in humans as it has been in mice. Hundreds of donors will be recruited for the new treatment - which is called leukocyte infusion therapy - and a process similar to platelet donation will be used to collect the granulocytes.