ARTICLE IN “THE MAIL ON SUNDAY” JANUARY 18TH 2009-01-27
By Nic Fleming
Taking the Pill or having hormone replacement therapy can trigger cancer-causing gene mutations, say scientists.
A study to be published tomorrow has identified how the hormone oestrogen in oral contraceptives and HRT pills can start a biochemical chain reaction that undermines women’s natural defences against cancer.
Researchers found oestrogen plays a key role in fighting off infections such as the common cold. However, they also discovered that exposure to high levels can trigger genetic mutations that can cause cancer.
While an association between oestrogen and cancer has long been known, the new findings provides the first clear evidence of how they are linked and could help scientists develop new ways to treat the disease.
Dr Svend Petersen-Mahrt, at Cancer Research UK’s ‘Clare Hall Laboratories in South Mimms, Hertfordshire, said: “We found oestrogen plays an important role in generating the diversity in the immune system that helps our bodies fight off a range of infections.
While this is beneficial for a healthy immune response, prolonged exposure will lead to genetic changes in other parts of the body which have been found to cause cancer.”
Dr Lesley Walker, director of cancer information at Cancer Research UK, said: “This finding is very important because scientists have long wrestled with the task of explaining the link between oestrogen and cancer.
The link is particularly pertinent to women receiving increased amounts of oestrogen for prolonged periods, during HRT for instance.”
The ‘ Million Women Study’, in 2003, found that post-menopausal women who used HRT were 22 per cent more likely to die from breast cancer than non-users.
Studies also suggest that the more than three million British women who take the combined contraceptive Pill, which contains oestrogen, are at an increased risk of breast cancer. The dangers are greatest for those with a family history of the disease.
Dr Peterson-Mahrt, lead author of the study to be published in the Journal of Experimental Medicine, made the oestrogen-link discovery in tests on mice in which he examined white blood cells that become activated when they encounter bacteria or viruses.
These immune system cells undergo mutations in their genetic code, enabling them to produce new antibodies to combat invaders. It was found that oestrogen helps to start this process by triggering the production of an enzyme called AID in the immune system’s cells. The researchers observed that higher than normal levels of AID caused immune system cell mutations associated with cancer.
Dr Petersen-Mahrt also showed elevated oestrogen led to AID production in breast, ovary, egg and prostate cells.
Previous work has shown this can also trigger cancer-causing gene changes.
A record number of people are on Valium in the credit crunch, with the antidepressant being prescribed somewhere in England every six seconds.
The Prescription Pricing Authority revealed that in England in the third quarter of last year, the number of Valium prescriptions leapt by nine per cent compared with the same period in 2006. In 1998, there were 3.98 million Valium prescriptions. The 2008 figure is expected to be 4.8 million.