But Myriad said the materials it patents are taken out of their naturally occurring context and isolated from the body and, therefore, are not works of nature.
Richard Marsh, Myriad executive vice president and general counsel, said the Supreme Court decision in the related case was distinct from Myriad's situation because it involved a process for testing drug levels versus Myriad's claim over DNA material isolated from the body.
"In our case, isolated DNA, isolated from the human genome, is not found in nature," Marsh said in an interview after the court hearing.
But the ACLU argues that even out of the body, isolated DNA materials remain a product of nature and are ineligible for patenting. By patenting the materials, Myriad can deny other researchers the opportunity to do research on them and develop different tests for measuring the risk a woman carries of gene-related breast and ovarian cancer, the group said.
"We need to be sure that natural things and all natural laws are available to all mankind," Chris Hansen, an ACLU lawyer, told the appeals court, according to Bloomberg News. The Myriad claims "cover every conceivable form of DNA."
The ACLU position was backed by the Justice Department, which represented the government in place of the U.S. Patent and Trademark Office, which normally appears in such cases.
Justice Department lawyer Melissa Patterson said that isolation of a specific gene was insignificant. She likened it to extracting coal from the ground.
"Some of these claims preclude access to a product of nature," Patterson said, according to Bloomberg. "Can the public still use and exploit that in new and different ways?"
Sandra Park, an ACLU attorney, said the appellate judges focused on where to draw the line between what is patent eligible when an entity is removed from its normal place in nature.
"That's why [the judges] were talking about various analogies, [such as] removing the wood from the trunk of a tree for a baseball bat, and would that mean that piece of wood would become patentable," Park said in a phone interview after the hearing. "Similarly, if you know exactly where to cut a kidney in order to remove it for transplant, does that mean the kidney that has been removed from one body has become a patentable thing."
The ACLU initially won the case in a ruling from a district court in New York. The Federal Circuit in its earlier 2-1 ruling favored Myriad.
But then in March, the Supreme Court ordered another look at the case in light of a case that involved a Mayo Clinic suit over patents held by Nestle's Prometheus unit that covered tests used to help determine the dosage of medicines. The high court ruled in Mayo's favor, saying the tests cover natural phenomena and can't be patented.
Circuit Judge Kimberly Moore, who last year sided with Myriad, wondered Friday about the effect of ruling that isolated DNA can't receive legal protection. The biotechnology industry has been getting patents on genes for decades and has come to rely on that, she said, according to Bloomberg News.
"There's a lot of money at stake," Moore said. "If it was so obvious it wasn't patentable, why wasn't it brought up before in the past 30 years?"
Myriad has said an adverse ruling should not affect its bottom line because the patents in questions are set to expire within a few years and it is developing other products.
But the biotechnology industry argues that it will have a much more difficult time raising money for research if discoveries related to genes cannot be patented.