An extensive survey of DNA samples from nearly 50,000 women, half of whom had breast cancer, has revealed a common gene mutation that holds 60 per cent increased risk of breast cancer.
Douglas Easton at the UK based University of Cambridge says that the gene mutation was observed in one out of six women during the study.
The researchers say that the newly identified gene variant, in the gene called fibroblast growth factor receptor 2 (FGFR2), is the most important genetic risk factor for breast cancer identified in about a decade, due to its widespread prevalence.
During the course of study, researchers specifically looked for small changes in the genetic code known as single nucleotide polymorphisms (SNPs) that are associated with breast cancer.
They found that women who carried one faulty copy of FGFR2 had a 20 per cent elevated risk of breast cancer, while those with two altered versions faced up to a 60 per cent greater chance of the illness. They say that one in six women was found to have two altered versions of the gene variant.
"This is probably the most important paper on breast cancer genetics since the cloning of BRCA2 in 1995," the New Scientist quoted Georgia Chenevix-Trench at the Queensland Institute of Medical Research in Australia, who collaborated with Easton on the new study, as saying.
A similar link between FGFR2 and cancer among women enrolled in the US-based Nurses' Health Study was found by another group of researchers.
"This finding opens up new avenues of research into the causes and prevention of breast cancer by identifying a new biological pathway relevant to risk of the disease," says David Hunter of the Harvard School of Public Health in Boston, Massachusetts, US, who contributed to both new studies.
Scientists say that mutations in the FGFR2 gene appear to relate cell growth or cell signalling.
"We're very excited by these results because the regions we identified don't contain previously known inherited cancer genes. This opens the door to new research directions," says Easton.
The researchers, however, are hesitant to advocate testing women for the FGFR2 gene.
"It is premature to recommend screening women for these variants" until scientists know more about other genetic risk factors, says Hunter.