More Breast Cancer Genes Identified

Scientists on Sunday announced they had uncovered four more genes that play a role in breast cancer, widening the portrait of one of the stealthiest slayers of women.

Until now, only about 25 percent of the genes that are 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 additional four percent.

British-led researchers found them after sifting through the DNA of nearly 50,000 women, half of them healthy and half of them patients with breast cancer.

Telltale "tags" of DNA code among the breast cancer group highlighted the four genes.

Their study is published by Nature, the British science journal.

Genetic causes account for between five and 10 percent of breast cancer cases, with "lifestyle factors" such as smoking and environmental factors accounting for the rest.

Flawed versions of the four genes are common in the general population, the paper said.

The good news, though, is that the genes are considered a relatively low hazard, meaning that women who have them run a comparatively small risk of developing cancer.

By contrast, the notorious breast cancer genes BRCA1 and BRCA2 are relatively rare in the population but women who have them run a high risk of the disease.

Diagnostic tests for BRCA1 and BRCA2 are helping to save many lives, as they alert women at risk to have regular breast scans.

Because the four newly-identified genes are so common yet relatively low-risk, individual tests for them may be unsuitable, Cancer Research UK, whose scientists led the massive investigation, said in a press release.

However, "as more of these "low-risk" genes are found it may be possible to design tests for a combination of genes," it said. "This could help doctors make decisions about prevention, diagnosis and treatment for women who inherit faults in one or more of these genes."

Much remains to be learnt about the four genes, especially whether they react with each other or with lifestyle factors in a way that boosts the risk for some women, it added.

Breast cancer is the commonest cancer to strike women, the World Health Organisation said in February 2006.

In 2005, breast cancer caused 502,000 deaths, accounting for seven percent of all cancer mortalities and almost one percent of all deaths worldwide.

Silhouettes representing breast cancer victims. Scientists on Sunday announced they had uncovered four more genes that play a role in breast cancer.