Factors such as hormone treatment, alcohol consumption, obesity and giving birth to a first child later in life have all been linked to a higher risk of [...]]]> AFP – Hormone replacement therapy and lifestyle choices do not boost the risk of breast cancer associated with a dozen common genetic mutations, according to a study published Wednesday.

Factors such as hormone treatment, alcohol consumption, obesity and giving birth to a first child later in life have all been linked to a higher risk of breast cancer.

A number of common genetic variations also correlate with the disease, albeit weakly.

Earlier research suggested that combining the two types of risk factors could amplify the overall danger, but results were inconclusive.

To help tease apart genetic and non-genetic influences, scientists led by Ruth Travis at the University of Oxford examined the medical histories of some 17,350 women, 7,160 of whom had developed breast cancer.

All of the participants provided blood samples for genetic testing and information on lifestyle habits. Most of the women were post-menopausal.

The researchers looked for 12 variants in the women’s DNA known to boost the danger of cancer.

They also measured 10 environmental risk factors: age at puberty, number of births, age at first birth, breastfeeding, menopausal status, age at menopause, use of hormone therapy, body fat, height and alcohol intake.

Surprisingly, none of the 120 possible match-ups between a single genetic variant and a behavioural or body-type risk factor showed a statistically significant increase in breast cancer risk.

“There was no convincing evidence for gene-environment interaction,” the researchers concluded.

The study did not cover data on the BRCA1 and BRCA2 genes, which have a far stronger association to breast cancer than the other genetic variants examined but are much rarer.

“Genes account for only a small proportion of breast cancers for most women and for most women the main risk remains the lifestyle factors,” said Oxford’s Jane Green, a co-author of the study.

Via: france24.com

Experts had suggested there might be dangerous interactions between genes that increase the risk of breast cancer and other factors such as taking HRT. This would [...]]]> Hormone replacement therapy and lifestyle choices do not boost the risk of breast cancer in women who have faulty genes linked with the disease, according to a a new study.

Experts had suggested there might be dangerous interactions between genes that increase the risk of breast cancer and other factors such as taking HRT. This would place such women at a particularly high risk of breast cancer.

However, researchers from Oxford University have found this isn’t the case meaning people aren’t completely at the mercy of their own DNA.

They studied more than seven thousand women with breast cancer and over ten thousand women without it. All of the women provided a blood sample for genetic testing and information about other risk factors like obesity, alcohol consumption and hormone replacement therapy.

The scientists used a statistical analysis to examine the relationship between genetic and lifestyle factors.

They found that although genetic mutations and lifestyle choices both contribute to cancer, they do so separately and do not mix for a more deadly effect.

The genetic mutations studied are carried in up to 60 per cent of women and increase a woman’s breast cancer risk up to a fifth.

The study, published in the medical journal The Lancet, did not include the rare BRCA genes which dramatically increase the risk of breast cancer.

Study author Ruth Travis from the Cancer Epidemiology Unit at Oxford, said it was reassuring she and colleagues didn’t find any proof of synergy between breast cancer mutations and lifestyle factors.

‘There’s a danger of feeling you’re at the fate of your genes,’ Dr Travis said.

‘But whatever you’re born with, there are things you can do to modify your risk.’

Experts said lifestyle factors are often more important in avoiding breast cancer than genetic ones. For example, being overweight elevates your risk by 40 per cent while taking hormone replacement therapy doubles it.

Susan Gapstur, vice president of epidemiology at the American Cancer Society, said the research underlined the complexity of breast cancer and that scientists still don’t completely understand what triggers it.

‘It likely won’t be a single genetic factor (that causes breast cancer) but maybe several genetic variants in combination and some environmental factors,’ she said.

The latest study was paid for by Britain’s Medical Research Council and Cancer Research UK.

Via: dailymail.co.uk