Cholesterol by-product linked to breast cancer in mice
A by-product of cholesterol breakdown could contribute to the growth and spread of breast cancer, a US study has revealed.
The study suggests that controlling cholesterol could offer a way to protect some women against the disease, but more research is needed.
"As the research was only done in the lab, it's a long way from showing that taking statins will lower a woman's chances of developing the disease" - Dr Emma Smith, Cancer Research UK
Scientists from the Duke Cancer Institute, publishing their findings in the journal Science, showed that a specific breakdown product of cholesterol known as 27HC promoted the growth and spread of breast cancer in mice.
When mice with breast cancer were treated with daily injections of 27HC, the researchers found their tumours grew more rapidly than in mice who had not been treated.
The researchers suggest that 27HC mimics the hormone oestrogen and helps switch on two receptor molecules that promote tumour growth and spread. One is known as the oestrogen receptor, the other is the Liver X receptor.
Looking at human breast cancer samples, the researchers found that the most aggressive tumours tended to produce the highest levels of the molecule that converts cholesterol to 27HC.
Senior author Donald McDonnell, chair of the Department of Pharmacology and Cancer Biology at Duke, said: "Human breast tumours, because they express this enzyme to make 27HC, are making an oestrogen-like molecule that can promote the growth of the tumour."
"A lot of studies have shown a connection between obesity and breast cancer, and specifically that elevated cholesterol is associated with breast cancer risk, but no mechanism has been identified", he added.
McDonnell believes the findings could offer a way to reduce the risk of breast cancer by keeping cholesterol in check, either with cholesterol-reducing statins or a healthy diet.
Dr Emma Smith, Cancer Research UK's senior science communications officer, said this new link between cholesterol and breast cancer in mice is intriguing, but it's too early to say how this could help tackle breast cancer in the future.
Dr Smith added, "As the research was only done in the lab, it's a long way from showing that taking statins will lower a woman's chances of developing the disease. As things stand, until we know more about the effects of statins on cancer risk, the best ways to cut the risk of developing breast cancer are to stay a healthy weight, cut down on alcohol and keep active."
Copyright Press Association 2013