A Silicon Valley startup is launching online sales of a $249 saliva-based test for the genetic risk of breast cancer. The price tag puts the test within reach of many patients who cannot afford similar tests that often cost at least $1,500.

Color Genomics, of Burlingame, California, has raised $15 million from investors including Yahoo co-founder Jerry Yang, PayPal co-founder Max Levchin and Steve Jobs’ widow Laurene Powell Jobs, as Fortune reports. It has also earned the support and collaboration of Dr. Mary-Claire King, a leading geneticist who discovered one of the two genes most commonly found to have mutations linked to breast cancer.

Breast cancer is the second-leading cause of death among women in the U.S. and 10 to 15 percent of breast and ovarian cancers are due to inherited genetic mutations. A woman who has a mutation on her BRCA1 gene -- the one discovered by King -- is 81 percent more likely to develop breast cancer by the time she turns 80 than a woman without a mutation.

Fortune says about half of women who carry mutations that put them at risk of developing breast and ovarian cancer cannot currently receive coverage for these tests under their insurance plan. Color Genomics plans to offer free testing to women who can't afford testing at the company’s low price, the New York Times reports.

Still, a genetic test is only as useful as scientists’ knowledge of genetics. Easy access to genetic tests raises questions about what women should do if they are found to have a mutation that is not definitively linked to cancer. That scenario may create anxiety or lead to unnecessary procedures, similar to the way a false positive in breast cancer screening can prompt a patient to undergo invasive tests such as a biopsy. 

“We have to be careful that we are not just increasing this group of worried-well who have incomplete information,” Dr. Kenneth Offit, chief of the clinical genetics service at Memorial Sloan Kettering Cancer Center in New York City, told the New York Times.

About 2 percent of genetic variations analyzed by Myriad Genetics, a leader in genetic testing, are indefinite, the Times reports. An effort launched Tuesday by Myriad and Quest Diagnostics, called BRCA Share, will create a data-sharing system that companies may pay to access for further research in hopes of lowering that rate.