Scientists at Canada's McGill University say blocking the enzyme PTP1B delayed cancer in mice that also respond to Herceptin. They add development of new drugs that can block the enzyme could well boost the effectiveness of other therapies in humans. The team concentrated on a strain of mice that develops breast cancer as the result of over-activity in the Her-2 gene, a trigger in about one quarter of all breast cancer cases and a biomarker for Heceptin. In addition to delaying the onset of breast tumors, researchers said deleting PTP1B also prevented secondary lung tumors.They noted that in animal studies, the benefits of treatment lasted two months after two weeks of therapy.

- here's the report on the research from the BBC