Scientists have identified four new genes that significantly affect a woman's risk of developing breast cancer, the science journal Nature reported on Sunday.

"The finding could allow doctors to predict cancer risk more accurately, and to guide treatments to prevent and cure the disease, but more important is what it might tell researchers about how the disease works," said Douglas Easton of the University of Cambridge, a member of the team that made the discovery.

Breast cancer is known to have a strong genetic influence. But until now, only about 25 percent of the genes suspected to cause inherited breast cancer have been identified.

The new culprits--flawed versions of genes called FGFR2, TNRC9, MAP3K1 and LSP1 -- are believed to account for an another four percent.

To search for some of the many other genes thought to make small differences to a woman's breast cancer risk, Easton and his colleagues compared the genomes of some 4,400 women with breast cancer with those of about 4,300 who did not have the disease, the report said.

They identified 30 differences in single DNA bases that seemed to be linked to the disease. These were then compared in more than 20,000 women with breast cancer and in a similar number of controls.

Three of the newly discovered genes are involved in controlling the growth of cells. The gene with the strongest association was fibroblast growth factor receptor 2, or FGFR2.

Women who have two copies of the high-risk version of this gene - about 16 percent of the population - have a 60 percent greater chance of developing breast cancer than do those with no copies of the gene, Easton and his colleagues found.