Enzyme Deficiency May Contribute To Liver Cancer, Mount Sinai Research Indicates

Using a knockout mouse model, the team has found that the likelihood of hepatoma, or primary liver cancer, increases substantially when half the normal amount of an enzyme called Plk4 is present. Furthermore, 60 per cent of patients with hepatoma were missing one copy of the Plk4 gene in their cancers. The genetic basis for hepatoma has not previously been extensively explored.

The study is published today in the August edition of the prestigious science journal, Nature Genetics.

"Our study indicates that loss of one copy of Plk4 is a major risk factor for primary liver cancer," says Dr. Carol Swallow, a surgical oncologist at Mount Sinai Hospital and an Associate Professor of Surgery at University of Toronto.

"This represents a major advance in our understanding of hepatoma at a molecular level and provides insight into who may be predisposed to this type of cancer genetically."

Dr. Swallow and her co-investigators, Dr. Jim Dennis, Senior Investigator at the SLRI, and Mike Ko, a PhD candidate at the University of Toronto, believe that this finding has important implications for screening and early detection.

The American Cancer Society estimates that there will be 667,000 new cases of liver cancer worldwide in 2005, with 83 per cent of them occurring in developing countries, particularly in Southeast Asia. The disease is also more prevalent in men than it is in women.

"Unlike many common cancers, the incidence of hepatoma is increasing in both developed and developing countries," said Dr. Swallow.

About Mount Sinai Hospital:
Mount Sinai Hospital is recognized nationally and internationally for its excellence in the provision of compassionate patient care, teaching and research. Its key priority programs are Women's and Infants' Health, Surgical Subspecialties and Oncology, Internal Medicine and Subspecialties, and the Samuel Lunenfeld Research Institute. It is a University of Toronto-affiliated patient care, teaching and research centre. Visit http://www.mtsinai.on.ca for more information about Mount Sinai Hospital.

About The Samuel Lunenfeld Research Institute
Established in 1985, the SLRI at Mount Sinai Hospital in Toronto is one of the world's leading centres for biomedical research. The Institute is part of Mount Sinai Hospital, an internationally recognized 440-bed acute care academic health centre affiliated with the University of Toronto. SLRI has 513 research, administrative and support staff, 100,000 square feet of laboratory space and a 25,000-square-foot pre-clinical research lab. For more information about SLRI research, visit http://www.mshri.on.ca