A VeriChip microchip held in a pair of tweezers is displayed in this May 2002 file photo in Boca Raton, Fla. Although the chips received U.S. Food and Drug Administration approval for use in humans, studies for more than a decade have linked the implants to malignant tumors in lab mice and rats.

When the U.S. Food and Drug Administration approved implanting microchips in humans, the manufacturer said it would save lives, letting doctors scan the tiny transponders to access patients’ medical records almost instantly. The FDA found “reasonable assurance” the device was safe. A sub-agency called it one of 2005’s top “innovative technologies.”

But neither the company nor the regulators publicly mentioned a series of veterinary and toxicology studies, dating to the mid-1990s, stating that implants had “induced” malignant tumors in lab mice and rats.

“The transponders were the cause of the tumors,” said Keith Johnson, a retired toxicologic pathologist, explaining the findings of a 1996 study he led.

Leading cancer specialists reviewed the research for The Associated Press and, while cautioning that animal test results do not necessarily apply to humans, said the findings troubled them. All urged further research before the glass-encased transponders are widely implanted in people.

‘Approved by the FDA’

To date, about 2,000 radio frequency identification, or RFID, chips have been implanted in humans worldwide, according to VeriChip Corp. The company, which sees a target market of 45 million Americans for its medical monitoring chips, insists the devices are safe.

Scott Silverman, chairman and chief executive officer of the Delray Beach, Fla., company, said management was “not aware of any studies that have resulted in malignant tumors” in laboratory animals.

The FDA also stands by its approval of the technology but declined AP requests to specify what studies it reviewed before approving the implants.

The agency is overseen by the Department of Health and Human Services, which, at the time of VeriChip’s approval, was headed by Tommy Thompson. Two weeks after the device’s approval took effect on Jan. 10, 2005, Thompson left his Cabinet post and by July was a board member of VeriChip Corp. and its parent company, Applied Digital Solutions. He was compensated in cash and stock options.

Thompson, until recently a candidate for the 2008 Republican presidential nomination, says he had no personal relationship with the company as the VeriChip was being evaluated and played no role in FDA’s approval.

Also making no mention of the findings on animal tumors was a June report by the ethics committee of the American Medical Association, which touted implantable RFID devices.

Dr. Steven Stack, an AMA board member, said committee members had not reviewed, or even been aware of, the literature on cancer in chipped animals.

Studies link cancer, chips

Published in veterinary and toxicology journals between 1996 and 2006, the studies found that lab mice and rats injected with microchips sometimes developed subcutaneous “sarcomas” – malignant tumors, most of them encasing the implants.

Caveats accompanied the findings. “Blind leaps from the detection of tumors to the prediction of human health risk should be avoided,” one study cautioned. Also, because none of the studies had a control group of animals that did not get chips, the normal rate of tumors cannot be determined and compared to the rate with chips implanted.

Still, specialists at some cancer institutions said the findings raised red flags.

“There’s no way in the world, having read this information, that I would have one of those chips implanted in my skin, or in one of my family members,” said Dr. Robert Benezra, head of the Cancer Biology Genetics Program at the Memorial Sloan-Kettering Cancer Center in New York.

Before humans are implanted on a large scale, he said, testing should be done on larger animals, such as dogs or monkeys.

Dr. George Demetri, director of the Center for Sarcoma and Bone Oncology at the Dana-Farber Cancer Institute in Boston, said even though the tumor incidences were “reasonably small,” the research underscored “certainly real risks” in RFID implants.

In humans, sarcomas can range from the highly curable to “tumors that are incredibly aggressive and can kill people in three to six months,” he said.

The product that VeriChip Corp. won approval for use in humans is an electronic capsule the size of two grains of rice. When scanned, it transmits a code that allows medics to access a patient’s medical records.