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The University of Cambridge has posted a video showing how and explaining why it uses mice to test cancer drugs for humans.

Cambridge used the video as an opportunity to be frank about its use of mice -- defending the necessity of it, but also focussing on animal welfare and alternatives the university is pursuing to try and reduce and replace animal tests. "As part of our commitment to openness, in our new film, we look inside one of our facilities, where mice are helping our scientists understand how cancers develop," explains the university in a blog post.


The video was released to coincide with World Day for Animals in Laboratories (held on 24 April) and offers a rare insight into a world usually closed to the public. Animal rights activists took to the streets of Cambridge this weekend to protest against experiments taking place at the university and at AstraZeneca's new headquarters on the biomedical campus.

The film reveals around 5,000 mice at the University of Cambridge are being used to test cancer drugs. Professor of biochemistry Gerard Evan explained specifically how mice were being used to learn more about pancreatic and lung cancer. "We have to have all the cells that are in that deranged tissue and understand how they're all talking to each other and interacting with one another. The only way we know of doing that are actually in deranged tissues as they are," he says in the video.

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Evans also sheds light on why mice, as opposed to other animals, are often used in medical experiments. "Mice are the closest we can get experimentally to human beings," he says. "Obviously we could get much closer, but then there would be even more problems associated with working with organisms that are, if you like, more intelligent and closer to human beings."

Mice are also easy to breed and maintain -- something that is important for effective testing and ensuring animals are kept in humane conditions. "Good animal welfare and good science go hand in hand," explains the video. All of the animals used by the University of Cambridge are bred in captivity and their cages are checked at least once a day, both to see that they have enough food and water and to check if animals are healthy.

The mice are routinely checked to see if they have developed tumours and whether they are in pain or discomfort. Many of the mice have been genetically engineered to be prone to cancers and others have human cancer cells transplanted into them.


The video shows how the mice are anaesthetised and scanned to see if the drugs being used are slowing or even reversing tumour growth. The video says that the animals are usually back on their feet again within around 20 minutes. The primary benefit of being able to perform these tests on mice, says Evans, is that "you can do all of the things you would like to be able to do with patients -- you can understand and investigate all of those things in an experimental model". "We only use animals in research where there are no alternatives," he continues. The university says it tries keep animal use to a minimum, and ultimately is interested in replacing animal testing models wherever it can.

In 2013, Meritxell Huch who works at the University of Cambridge's Gordon Institute won the 3Rs prize for discovering a new way to test the effect of drugs on the liver without using live animals, and instead growing liver tissue out of mouse stem cells.

The video argues that nearly all drugs have been tested on animals at some point and that ultimately this is the best way of testing new drugs. "You can get a long, long way with an experimental animal model," says Evans.