High cholesterol causes breast cancer, study shows

  
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British researchers have discovered a relationship between high cholesterol levels in women, and breast cancer. EurActiv France reports.

Heart disease was a known factor in developing breast cancer, but now it has become clear that cholesterol also plays its part. British researchers carried out a study to determine whether there was a relationship between high cholesterol and cancer. It found that in those without a risk factor for cancer, normal levels of cholesterol in the blood are at 1.6 g/l, whereas with a risk factor, cholesterol levels dropped to 1.3 g/l.

Too much cholesterol in the blood can cause problems with arteries that irrigate the heart. These diseases can cause heart attacks and strokes, the two leading causes of death in Europe. According to the European Heart Network (EHN), approximately four million Europeans die from cardiovascular diseases every year.

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Scientists surveyed one million patients in the UK over 13 years, 664,159 of which were women. The study showed that out of the 22,938 women suffering hypercholesterolemia (high levels of cholesterol in the blood), 9,312 developed breast cancer.

This ratio is higher than in people with normal cholesterol levels. The scientists calculated that high cholesterol levels in the blood increases the chances of developing breast cancer by 64%.

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Rahul Potlurim, researcher at the Aston University in Birmingham, is cautious. “This is a primary study. Time and more research are needed to confirm the results,” he said.

“It is a preliminary study, but the results are promising. We found a significant relationship between hypercholesterolemia and developing breast cancer which must be explored in greater detail,” said the researcher. He believes that if the relationship between the two is confirmed, statins could reduce the risk of cancer, as well as cholesterol levels.

Statins are the most common treatment to reduce cholesterol levels in blood. Five million patients in France take the drug.

Obesity

An earlier study already established a relationship between obesity and breast cancer and that this relationship was even stronger after the menopause.

Obesity can also affect the aggressiveness of a cancer. The cells in the fatty body tissue surrounding the breast modify the secretion of certain proteins, including proteins for inflammation in the presence of a cancerous tumour. These cells gradually develop an interaction with the tumour. It increases its “colonisation potential” and therefore its aggressiveness.

This is why overweight women are more likely to develop breast cancer. According to the International Agency for Research on Cancer (IARC), 3.3% of cancer cases in women are due to obesity.

Carcinogen cholesterol molecules

An American study exposed the cancerous properties of a cholesterol molecule: 27-hydroxycholesterol (27HC). It acts the same way as oestrogen, well known for contributing to the development of cancerous breast cells.

Scientists gave 27HC to mice suffering from breast cancer. They found that the molecule accelerates the progression of tumours and metastases (spread of a cancer from one organ to another). The same results were recorded on malignant breast tissue from humans.

The researchers also discovered that by treating guinea-pigs with anti-oestrogen, it stopped 27HC’s cancerous activity.

External links: 

European Society of Cardiology

Science  AAAS

  • Study on 27-Hydroxycholesterol
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