Abbott Laboratories has sued one of the world's top cancer researchers, claiming he and Children's Hospital in Boston stole the credit for developing a promising drug that cuts off the blood supply to tumours.

Dr. Judah Folkman fraudulently told US patent reviewers that he discovered tumour-inhibiting properties in a small section of an angiostatin protein known as Kringle 5, according to the lawsuit filed in US District Court in Boston by Abbott Laboratories.

Angiostatin is one of two angiogenesis inhibitors credited to Folkman's lab at Children's Hospital. EntreMed, a Maryland biotech firm, is running clinical trials of both angiostatin and the other drug, endostatin.

As cancer fighters, the drugs appear to be especially powerful, at least in mice and rats. The lawsuit does not affect any of the clinical trials under way at hospitals around the country.

Abbott Laboratories and one of its researchers, Donald Davidson, are seeking compensation and $10 million in damages for the ``unlawful misappropriation of and conspiracy to steal an invention'' of a molecule, the lawsuit says.

According to the lawsuit, Folkman and his team took Davidson's research and violated a confidentiality agreement by trying to profit from it without Abbott's knowledge.

The suit claims Davidson was the first to discover and show that Kringle 5 inhibited the growth of blood vessels. Abbott is developing Kringle 5 as a cancer drug, but EntreMed attorney James Johnson said that company has patented it.

``This dispute comes down to Children's Hospital wanting to protect its patent rights and Abbott wanting to avoid paying any royalties,'' Folkman said. ``I have no personal interest in this matter and hope that Kringle 5 continues totest well and progresses from the laboratory to further stages of development so that it can eventually benefit patients.''

In a statement, Children's Hospital denied Abbott's claims and called them ``inflammatory and irresponsible charges.''