OncoMouse — The First Patented Animal, Built to Get Cancer

Philip Leder and Timothy Stewart's 1988 DuPont/Harvard patent on the OncoMouse describes the first genetically engineered animal ever patented — a mouse with an activated cancer gene, used to test cancer drugs.

What it covers

This patent covers a transgenic non-human mammal (specifically, a mouse) that has been genetically modified to carry an activated oncogene — a gene that causes cancer to develop. The oncogene is introduced into the mouse's fertilized egg using recombinant DNA techniques, so that every cell in the resulting animal carries the cancer-promoting gene. Because the oncogene is heritable, offspring of these mice also carry it, allowing researchers to produce consistent experimental animals for cancer research. The mice are predisposed to develop tumors at predictable rates and locations, making them far more useful as cancer research models than randomly induced tumors.

What it doesn't cover

• —The specific genetic technique (recombinant DNA/transgenic methods) — those are covered by separate foundational patents
• —Other transgenic animals beyond non-human mammals — later patent applications for fish, insects, and plants required separate proceedings
• —Human genetic modification — the patent explicitly covers non-human mammals; human germline editing remains unpatentable and illegal in most jurisdictions
• —Specific cancer drugs or treatments — the mouse is a research tool, not a therapy

The clever bit

The OncoMouse patent was the culmination of a decade-long debate: could an animal — a living thing — be patented? The 1980 Diamond v. Chakrabarty Supreme Court case had allowed patents on genetically modified bacteria ('anything under the sun made by man'), but animals were assumed to be different. The U.S. Patent and Trademark Office initially rejected Harvard's application on the grounds that animals were products of nature. After appeals and years of consideration, the USPTO granted the patent in 1988 — the first ever for a vertebrate animal. The mouse itself was engineered to carry the myc oncogene, one of the most studied cancer-promoting genes. DuPont commercialized it and charged cancer researchers licensing fees, which generated significant controversy in academia.

Why it matters

The OncoMouse patent fundamentally changed the relationship between academic research and intellectual property. Before it, research tools — cell lines, antibodies, genetic sequences — were generally shared freely. After it, universities and corporations began aggressively patenting biological research tools. The resulting licensing fees and 'reach-through' royalty demands on research findings created a significant controversy about whether patents on living organisms help or harm scientific progress. The patent expired in 2005, and today transgenic mice are standard research tools available from commercial suppliers. The OncoMouse's legal legacy — the patentability of genetically modified organisms — continues to shape biotechnology IP law.

Real-world examples

• 1.The OncoMouse was used in thousands of cancer research studies throughout the 1990s and 2000s — it became the standard animal model for breast cancer research
• 2.DuPont licensed the mouse to academic researchers under controversial 'reach-through' agreements claiming royalties on any discoveries made using it
• 3.Canada's Supreme Court refused to extend the patent to Canada in 2002, ruling 5-4 that higher life forms are not patentable under Canadian law — the same mouse was simultaneously patented in the U.S. and unpatentable in Canada

Glossary