Cancer, a genetic disease in which cells become abnormal and grow in an uncontrolled manner, continues to be one of the leading causes of death worldwide. The need to develop better, human-relevant models of cancer has never been greater, which is why NAVS has been funding the development of such models through the International Foundation for Ethical Research over the years.
While NAVS feels that cancer research is best approached through the use of human-relevant models, some researchers are moving their cancer models in directions that may not be helpful to cancer patients suffering from this complicated disease—by focusing on different animal models of the illness. Rodents are commonly used as models in this field, but a recent article in last month’s Lab Animal magazine highlighted a troubling new trend—the use of pigs for this purpose.
While some scientists agree with our concerns about pig cancer models and feel that using pigs for this reason is “absurd,” according to the article, others are beginning to view pigs as research tools that can fill the gaps between mice and humans, including Dr. Lawrence Schook of the University of Illinois. Dr. Schook, who believes that pigs won’t replace mouse models, but will instead be used as a transition to human clinical trials, was also quoted in this article as saying, “I’ve always viewed pigs as a big mouse”— a troubling statement on many levels.
Pigs are not mice. And neither animal is human. Cancer is tricky to study in these systems for many reasons. It is a very personalized condition, involving multiple genetic changes that occur as normal cells transition to cancerous ones that ultimately grow and spread. In a person, it can take decades for these changes to accumulate. In the lab, however, animals are genetically engineered to get cancer quickly and artificially.
Not to mention that when tumors do grow, they are growing in animals which have different anatomies, physiologies and genetic backgrounds than humans do. This impacts many things, including the tumor microenvironment — the cells, blood vessels, and molecules surrounding tumors — which is different in animals than in human patients. Because the tumor microenvironment is known to influence how tumor cells grow and spread, results from animal models may not be easily translated to people.
History has shown us that the vast majority of treatments developed in animal models ultimately fail in people. It doesn’t make sense, therefore, to continue exploiting mice, pigs or any other non-human animals for this purpose. Rather than perpetuating faulty science by continuing to generate new animal models as stand-ins for people, NAVS remains firmly committed to advancing smarter, more predictive non-animal models for cancer and other human health conditions.