US researchers have found an antibody that hunts down prostate cancer cells in mice and can destroy the killer disease even in an advanced stage, a study showed Monday.

The antibody, called F77, was found to bond more readily with cancerous prostate tissues and cells than with benign tissue and cells, and to promote the death of cancerous tissue, said the study published in the Proceedings of the National Academy of Science (PNAS).

When injected in mice, F77 bonded with tissue where prostate cancer was the primary cancer in almost all cases (97 percent) and in tissue cores where the cancer had metastasized around 85 percent of the time.

It recognized even androgen-independent cancer cells, present when prostate cancer is incurable, the study by researchers at the University of Pennsylvania showed.

F77 "initiated direct cell death of prostate cancer cells... and effectively prevented tumor outgrowth," it said.

But it did not target normal tissue, or tumor tissues in other parts of the body including the colon, kidney, cervix, pancreas, lung, skin or bladder, the study showed.

The antibody "shows promising potential for diagnosis and treatment of prostate cancer, especially for androgen-independent metastatic prostate cancer," which often spreads to the bones and is difficult to treat, the researchers wrote in PNAS.

Currently, the five-year survival rate for metastatic prostate cancer is just 34 percent, according to the study.

Prostate cancer is the second most common cancer among men, claiming half a million lives each year worldwide, according to the World Health Organisation (WHO).

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(c) 2009 AFP