A study of 16,000 women revealed that genetic mutations associated with breast size are linked to the disease. Researchers say some of these are involved in regulating the female sex hormone- estrogen, which can trigger the growth of both breasts and tumours, reports the Daily Mail.
While research has previously linked breast density, which is the amount of non-fat tissue, to an increased risk of cancer, there has been little evidence of a link with breast size.
Participants in this study carried out by a US company, were asked to give their bra size on a 10-point scale from smaller than AAA to larger than DDD. The genetic code of the women, who were all of European origin, was read by scientists who looked through millions of tiny mutations in their DNA, called single-nucleotide polymorphisms. Out of the seven that were strongly linked to breast size, three were also associated with breast cancer.
As reported by the Daily Mail, Dr Nicholas Eriksson of the California-based genetics firm 23andMe shared that it was the first substantial link between breast size and cancer, but added that much more research is needed before it could be strongly concluded.
He tells the daily that one out of the three mutations regulates the activity of the oestrogen receptor gene that plays a vital role in breast growth and in majority of breast cancer cases. Another is located in a region of a woman’s genome that often shows abnormalities in those with certain types of breast cancer.
The link was seen regardless of the women’s age, pregnancy and breastfeeding history and genetic ancestry, according to the study published in the journal BMC Medical Genetics.
However, the study’s lead author, Karin Michels, told The Daily Mail that these results did not mean those with small breasts could assume they were safe and urged all women to go for regular breast cancer screening.