Further evidence of vitamin D's role against breast cancer
almost twice as likely to develop breast cancer than women with
other versions of the gene, finds a new study, that supports
previous evidence of the vitamin's protective effect against the
disease.
But it demonstrates how the way in which the body utilises the vitamin is also important.
Dr Kay Colston and colleagues at St George's Hospital Medical School in London found that Caucasian women who have certain versions of the vitamin D receptor gene, which controls the action of vitamin D in the body, have a nearly two-fold greater risk of breast cancer than women with other versions of the gene.
They may also have a more aggressive form of the disease if it spreads, the researchers will report in the 15 August issue of Clinical Cancer Research (Vitamin D Receptor Gene Polymorphisms).
The findings support the idea that vitamin D plays a part in protecting the body against the disease and that different versions of the vitamin D receptor gene will affect this protective function.
Author Dr Michelle Guy said: "While it is known that 5 to 10 per cent of breast cancer cases are due to a genetic predisposition associated with well-characterised genes, like BRCA1, the underlying causes of the majority of all other breast cancers remain a mystery."
"We hope that by showing that natural variations in the vitamin D receptor gene can increase susceptibility to breast cancer, we are starting to unravel how breast cancer might develop in women who have no family history of the disease."
Scientists from St George's Hospital and the University of Birmingham reported earlier this year that breast tissue contains the enzyme that activates vitamin D, and levels of this enzyme are increased in breast tumours. Previously it was thought that the active form of vitamin D, calcitriol, which is a potent anti-cancer agent, was only made in the kidney.
In the new study, the researchers looked at the VDR gene of 398 women with breast cancer and 427 women without breast cancer. The women with breast cancer were significantly more likely to have a certain versions of the gene than the cancer-free women, they found.
The research is expected to offer progress in the future treatment for breast cancer, with risk assessment and drug regimes tailored to the individual patient.
It also adds to growing knowledge of the interaction of genes on the benefits of nutrients.
Professor Martin Wiseman, medical and scientific adviser of one of the charities funding the study, the World Cancer Research Fund, added: "This is an important study which begins to address questions about how diet and lifestyle interact with genetic factors to influence cancer risk, and why different people respond in different ways."
"Experimental studies such as this play a vital role in supporting the epidemiological research which together gives us a much fuller picture on how cancer is caused and so how to prevent it."
Britain has one of the highest breast cancer death rates in the world, according to Breast Cancer Research, with one woman in nine developing the disease during her lifetime. It is also the most common cancer among women across the European Union.
