It is not news that mice are used to test new drugs for diseases such as cancer. But it is now possible to have your very own “personalized animal model” for testing treatments for the tumor in your body.
While scientists have been implanting tumors into animals for decades, companies are now offering what some researchers are calling “avatars,” animals who can be injected with a part of the tumor that you have, says the New York Times. Researchers can then try different experimental (i.e., not FDA-approved) drugs and treatments on the mice.
That is, these mice are not lab mice. They’re mini-me mice.
The National Institutes of Health even held a workshop about personalized animal models earlier in September (pdf). Mice avatars are also being used to learn about how Type 1 diabetes develops and a scientist from Washington University in St. Louis has injected bacteria from human stomachs into that of mice, to investigate the effects of dietary changes.
The advantage of using tumors “freshly implanted from patients” instead of tumors cultured in a laboratory dish is that they are more closely resemble the conditions that humans have. As one University of Utah breast cancer researcher, Alana Welm, says “It’s the closest we can get to the real deal.”
Experts emphasize that there is no proof that the avatars can actually lead to efficacious treatments; a more practical way to determine if a drug may work in a patient is to test tumors for genetic mutations. As insurance does not cover the use of mice avatars, people can be paying tens of thousands of dollars to implant the animals with diseases but with minimal results, except for some dead avatars. In addition, a treatment that works in a mouse may not work in a human being:
…the stand-ins are not perfect surrogates. A tumor implanted under the skin of a mouse might not behave the same as it did in the human breast, lung or other organ from which it was extracted. Unlike people, the mice are bred to have a deficient immune system, so they will not reject the human tumor.
There are also practical problems. Sometimes, patient tumors do not grow in the mice at all, and it takes at least four months to create enough mice to test a reasonable number of drugs.
The tumors, bacteria and such are surgically implanted into the mice (hairless as they are bred to have deficient immune systems) under anesthesia.They are killed “if the tumor is removed for transplanting into more mice or is causing too much suffering.”
Most of those using avatars to find treatments for their diseases told the New York Times they felt no “personal attachment” to the mice who share a very intimate link with them. 9-year-old Michael Feeney has Ewing’s sarcoma, a type of bone cancer, and pieces of a tumor from his lungs are now in a number of mice avatars, on whom researchers are testing different drugs. His mother says that he was a “little upset to hear we would be giving mice cancer and that we might kill them” (or rather, actually will kill them), while noting that if they do point the way to a treatment to save her son, she will “love these mice forever.”
Is it too much to presume that a drug that works in a specially-bred mouse would have the same results in a human being? Is using animal avatars to find cures for individuals any different than using animals for lab tests and scientific experiments?
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Photo of hairless lab mice by Mike Mitchell (National Cancer Institute) via Wikimedia Commons