Researchers say they have identified gene variations which may play a role in developing common breast cancer. A study of women in Finland and Sweden found 121 variations in their DNA linked to this particular kind of cancer. The team think they are linked to oestrogen production – which plays a role in a breast cancer type afflicting post-menopausal women.
The findings might help identify women who might benefit from oestrogen-lowering drugs.The researchers examined the genetic makeup of thousands of women with and without breast cancer in Sweden and Finland.
They found 121 tiny variations in 15 different genes which they say appear to be linked to a woman’s risk of developing what is known as oestrogen receptor positive breast cancer.
The variations are in a section of DNA close to a gene responsible for producing oestrogen and the suggestion is that the variations may play a collective role in the production of the female sex hormone.
The individual impact of each variation is minimal but if a woman is dealt a combination of these variations, say the scientists, the higher her exposure to the hormone will be, and the higher the risk of cancer.
“Breast cancer genes have been identified, for example BRCA1, BRCA2, P53, ATM. These genes have been identified with breast cancer susceptibility but mainly in breast cancers of younger women,” says Dr Edison Liu of the Genome Institute of Singapore, who led the study.
“What we are finding here is potentially the genetic amplifiers for breast cancer in postmenopausal women which historically was considered not genetic in origin.”
It is already established that women who start menstruating early in life or who have a late menopause have an increased risk of breast cancer, because of their longer exposure to oestrogen. This research, says Dr Liu, may reveal the genetic element to the oestrogen equation.
“It’s like being dealt a bad hand in a poker game,” he says. “And this risk is greatly affected by other non-genetic factors like a woman’s reproductive history,” he says.