_ A 2006 study in France detected tumors in 4.1 percent of 1,260 microchipped mice. This was one of six studies in which the scientists did not set out to find microchip-induced cancer but noticed the growths incidentally. They were testing compounds on behalf of chemical and pharmaceutical companies; but they ruled out the compounds as the tumors' cause. Because researchers only noted the most obvious tumors, the French study said, "These incidences may therefore slightly underestimate the true occurrence" of cancer.
_ In 1997, a study in Germany found cancers in 1 percent of 4,279 chipped mice. The tumors "are clearly due to the implanted microchips," the authors wrote." (Source: Washington Post:Chip implants linked to Animal Tumors).