Although the experts said there is a considerable difference between humans and animals (it's easier to cause cancer in a laboratory mouse than a human said one veterinary oncologist for example), there was sufficient concern for them to call for more long term controlled studies to be done on larger animals and possibly humans as well.
RFID, short for Radio Frequency ID, microchips are identity chips used in a range of applications from identity tagging library books to cars to pets and now more recently, people. In animals and people they are inserted under the skin.
RFID chips usually contain two parts: an integrated circuit that stores information and a receiver-transmitter (also called a transponder) that senses when an appropriate scanning device is nearby and then transmits a radio frequency message to the device. The scanner picks up the radio signal and reads the information on the chip.
First used in animals, for instance to help find lost pets, RFID chips were approved for use in humans by the Food and Drug Administration (FDA) in 2004. They were hailed as a medical breakthrough, because they could be used to provide access to important medical information in situations where the patient is not able to do that for themselves.
A typical example that is cited is the case of an Alzheimer's patient who gets lost and ends up in a hospital where the staff scan the patient's arm and get an immediate readout of their essential medical information.
The devices used in humans are made by VeriChip Corp. a subsidiary of Applied Digital Solutions, of Delray Beach, Florida. Some 2,000 chips have been implanted in humans worldwide to date, and according to AP, the company, who insists the devices are safe, sees its target market for medical monitoring as 45 million Americans.
Scott Silverman, chairman and CEO of VeriChip Corp. said in a response to questions posed by AP that the company did not know about any studies that "resulted in malignant tumors in laboratory rats, mice and certainly not dogs or cats." He said millions of pets have RFID implants and there have been no reports of significant problems.
The articles cited by AP that were reviewed by the cancer experts were studies on lab mice and rats that sometimes developed sarcomas, or malignant tumours, after being implanted with microchips. The sarcomas sometimes encased the implants, said the AP report.
The articles were published in toxicology and veterinary journals between 1996 and 2006 and included:
- A study conducted in 1996 by (now retired) toxicologic pathologist Keith Johnson at the Dow Chemical Co. in Midland, Michigan. Johnson said in a phone interview with AP "the transponders were the cause of the tumors".
- A study conducted in Germany in 1997 that found 1 per cent of over 4,000 RFID chipped mice had cancer which the authors concluded were "clearly due to the implanted microchips".
- A study conducted in Ridgefield, Connecticut, in 1998, on 177 mice that suggested the incidence of cancer was raised by just over 10 per cent.
- A study conducted in France in 2006 where tumours were detected in 4.1 per cent of mice with microchip implants. The scientists were not looking for cancer induced by microchips when they started the study. They were testing chemicals but they ruled them out as the cause of the tumours.
However, according to AP, the reactions of the scientists who came from "pre-eminent cancer institutions" when they reviewed the studies were revealing.
For example, Dr Robert Benezra, who is head of the Cancer Biology Genetics Program at the Memorial Sloan-Kettering Cancer Center in New York said that:
"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."
Others said the studies raised "red flags" and that further studies using dogs and non-human primates were needed.
Catharine Paddock PhD (resource no longer available at ap.google.com)