Sydney, Nov 28 (UNI) Women who smoke and also have faulty breast cancer genes (BRCA) are at greater risk of breast cancer, a research claims.
According to a new Australian study, smoking almost doubles the risk of developing breast cancer among women with a strong family history of the disease or those having faulty BRCA1 or BRCA2 genes, also known as breast cancer genes.
''If you have a faulty breast cancer gene or a strong family history of breast cancer, not smoking may reduce your risk of developing breast cancer and you will also get all the other health benefits of not smoking.'' said Dr Mark Jenkins, a University of Melbourne researcher who was part of the international collaboration.
About one in 300 women has a faulty BRCA1 or BRCA2 gene.
Of those, between 20 and 40 per cent develops breast cancer by 50, rising to 60 per cent by the age of 70.
About half the women with faulty versions of these genes develops cancer by the age of 70.
The research found the risk was as low as 35 per cent among non-smokers, rising to almost double - 65 per cent - among smokers with a mutation, the Daily Telegraph reported.
''This study suggests that women with faulty genes can effectively halve their risk of developing breast cancer by quitting smoking,'' said Dr Jenkins.
The review, published in the journal Breast Cancer Research and Treatment, analysed data collected from 780 women involved in large breast cancer trials, including more than 300 from the Melbourne-based Australian Breast Cancer Family study.
All the women were under 50 and had a faulty BRCA gene and half had developed cancer.
An analysis found that the women who developed breast cancer were more likely to have smoked than those who were cancer free, Dr Jenkins said.
Women with a faulty BRCA1 gene had a 2.3 increased risk after smoking for five years or more, while BRCA2 smokers had a 2.6 increased risk.
The risk increased the longer a woman smoked, rising by about 7 per cent every year they maintained the habit.
Dr Jenkins said BRCA1 and BRCA2 genes, when functioning normally, repaired the DNA damage caused by carcinogens such as cigarette smoke.
Women with a faulty copy of the genes are less able to fix DNA damage.
''This study suggests that smoking plays a major role and adds to the growing body of evidence on the health dangers of smoking,'' Dr Jenkins added.