WASHINGTON -- Synthetically created combinations of DNA are not naturally occurring and are therefore patent-eligible, but whole genes such as BRCA1 and BRCA2 occur naturally and can't be patented, the Supreme Court ruled unanimously Thursday.

"The Patent Act permits patents to be issued to '[w]hoever invents or discovers any new and useful ... composition of matter,' but 'laws of nature, natural phenomena, and abstract ideas' are 'basic tools of scientific and technological work' that lie beyond the domain of patent protection," wrote Justice Clarence Thomas in the 9-0 decision.

The ruling came in a case entitled Association for Molecular Pathology v. Myriad Genetics. The petitioners argued that genes are a product of nature and therefore patents on BRCA1 and BRCA2 genes held by biotechnology firm Myriad Genetics were invalid. Salt Lake City-based Myriad Genetics argued that it could legally patent the genes because once they were isolated from the body, they were no longer a product of nature.

Mutations in BRCA1 and BRCA2 genes raise a woman's risk of developing breast and ovarian cancer.

A district court in 2010 ruled the patents invalid because they were products of nature. The Court of Appeals for the Federal Circuit in 2011 disagreed, setting up the case for the Supreme Court.

During oral arguments at the Supreme Court in April, Chief Justice John Roberts said he disagreed with the appellate court's reasoning. In that court, the judges likened the patents to the patenting of a baseball bat. A tree isn't patent eligible, but a bat -- once extracted from the tree and carved -- is eligible.

"The baseball bat is quite different," Roberts said. "You don't look at a tree and say, 'well, I've cut the branch here and cut it here and all of a sudden I've got a baseball bat.' You have to invent it, if you will."

Justice Stephen Breyer said he supported allowing companies like Myriad to be able to patent the process by which they find and extract certain gene segments -- just not genes themselves.

In its decision invalidating Myriad's patent, the Supreme Court said that "Myriad's principal contribution was uncovering the precise location and genetic sequence of the BRCA1 and BRCA2 genes ... Myriad did not create or alter either the genetic information encoded in the BCRA1 and BCRA2 genes or the genetic structure of the DNA. It found an important and useful gene, but groundbreaking, innovative, or even brilliant discovery does not by itself" meet the criteria for a patent.

In addition, "Myriad's claims are not saved by the fact that isolating DNA from the human genome severs the chemical bonds that bind gene molecules together," Thomas wrote. "The claims are not expressed in terms of chemical composition, nor do they rely on the chemical changes resulting from the isolation of a particular DNA section. Instead, they focus on the genetic information encoded in the BRCA1 and BRCA2 genes."

The justices said that it is important to note "what is not implicated by this decision. First, there are no method claims before this Court. Had Myriad created an innovative method of manipulating genes while searching for the BRCA1 and BRCA2 genes, it could possibly have sought a method patent. But the processes used by Myriad to isolate DNA were well understood by geneticists at the time of Myriad's patents ... and are not at issue in this case."

The ruling "is a validation that things that are wrong can be made right," Arupa Ganguly, PhD, one of the original plaintiffs in the case, told MedPage Today in a phone interview. "I'm ecstatic."

Ganguly, a professor of genetics at the University of Pennsylvania in Philadelphia, said her laboratory was asked by Myriad in 1999 to "cease and desist" from doing BRCA1 and BRCA2 tests because of Myriad's patents.

The ruling means a lot for patients because "testing can improve, prices can be controlled, and people can have more access" to the tests, Ganguly said, noting that before the patents were invalidated, researchers could do work on a patient's blood sample but could not share their test results with patients.

The ruling will allow more companies to get into the market for BRCA1 and BRCA2 tests, increasing competition and driving down prices, said Rebecca Nagy, MS, president of the National Society for Genetic Counselors.

The ruling "appears to ... open up the test to other labs as long as the technique they use goes straight from naturally occurring DNA," said Nagy, a certified genetic counselor at Ohio State University in Columbus. "That will have a huge impact on how we practice and on delivering services to these women."

The ruling was "somewhat of a compromise" because it still allows patenting of composite DNA (cDNA), she noted. "If the [genetic] test utilizes genomic DNA -- which many of them now do -- and they don't have to create a step to do cDNA, another lab is free to use that [test]."

Although most genetic tests today use whole DNA, there are some cases in which testing is more complete if cDNA is used, Nagy said.

Some have argued that invalidating the patents will discourage biotechnology firms from developing genetic tests, but Ganguly disagreed. "The commercial research is not about the natural [gene] sequence," she said. "The commercial interest is what you do with that gene sequence. Do you design something new? Or find a new pathway to target for therapy? That will go on just like before."