When Angelina Jolie announced last month that she decided to get a prophylactic double mastectomy, she based her decision on the presence of the BRCA1 gene in her body—a gene that was detected via a costly medical test.

The Supreme Court today unanimously struck down patents on BRCA1 and BRCA2—two genes linked to hereditary forms of breast and ovarian cancer—when the genes occur in the body. Myriad did not create or alter any of the genetic information of the BCRA1 and BRCA2 genes, and thus does not satisfy patenting requirements, according to the decision. “Myriad discovered the precise location and sequence of what are now known as the BRCA1 and BRCA2 genes,” Justice Clarence Thomas wrote for the court.

This ruling could lead to cheaper tests for individuals who may be at increased risk of developing cancer. If Myriad Genetics were allowed to hold exclusive patents on these genes, the company would have maintained sole rights to create medical tests that indicate whether an individual has mutations that would lead to elevated risk of developing these cancers.

The ruling should also affect the medical research community. Because the genes were patented, any researcher who found a new way to isolate the genes would not have been able to use it, since Myriad held patents on the genes themselves. The court’s decision removes that restriction.

On average, women have a 12 to 13 percent risk of developing breast cancer over their lifetimes, but that risk spikes with the presence of mutations in the BRCA1 and BRCA2 genes—jumping to between 50 and 80 percent for breast cancer and 20 and 50 percent for ovarian cancer, the decision notes.

Myriad had identified the exact location of the BRCA1 and BRCA2 genes; it had not discovered that heredity plays a role in establishing risk of breast and ovarian cancer. “Myriad did not create anything,” Thomas wrote. “To be sure, it found an important and useful gene, but separating that gene from its surrounding genetic material is not an act of invention.” “I’m just incredibly relieved,” says Lisbeth Ceriani, a breast cancer survivor and original plaintiff who struggled to afford Myriad's test.

Jolie wrote in the New York Times last month that “the cost of testing for BRCA1 and BRCA2, at more than $3,000 in the United States, remains an obstacle for many women.”

The court also determined that synthetically created DNA, cDNA, which contains the same information as its natural cousin but omits portions within the DNA segment that do not code for proteins, is patentable. Sandra Park, a senior staff attorney for the American Civil Liberties Union, says that this decision will not impact genetic testing since cDNA is not necessary for that process.