A drug routinely used to treat high blood pressure may also protect against cancer, researchers in Glasgow University's medical school believe.
The scientists stress that the connection has yet to be proved, but say their findings so far raise "exciting possibilities".
Their report, published in The Lancet today, follows concerns in recent years that some hypertensive drugs could increase the risk of cancer. The Glasgow team has already shown that two widely used classes of drugs, beta-blockers and calcium channel-blockers, do not appear to increase cancer risks. But the latest report reveals that ACE (angiotensin-converting enzyme) inhibitor drugs may have the hidden dividend of protecting against cancer.
The study is based on records from the Glasgow Blood Pressure Clinic, which cover more than 10,000 patients since the late 1960s, compared with two control populations, including records from the West of Scotland Cancer Surveillance Unit.
The team found that the relative risk for cancer in the group taking ACE inhibitors was 28 per cent lower than the value expected from the control population, while for fatal cancer the relative risk was 35 per cent lower than expected.
Tony Lever, professor of medicine in Glasgow's department of medicine and therapeutics, and the report's first-named author, warned that further studies were essential.
"This is not like a clinical trial. It is a retrospective analysis of patients already treated with the drug for completely different purposes, without an investigation of cancer in mind at all,'' he said.
"It is the first glow in the dark rather than illuminating the room. But it is potentially very important indeed. You need the glow in order to find out where the light switch is.''