For the last several years, researchers at the University of Illinois interested in improving screening programs for cancer have studied gene expression in mice, humans, and pigs in an effort to create a large-animal model that is more relevant to human cancers.
Now, a genetically engineered pig is providing that large-animal model, and due to the GE, tumors can be induced at any tissue site at any given time.
Lawrence Schook, a geneticist in the University of Illinois Department of Animal Sciences, said that the "oncopig" model holds great promise not only in understanding and detecting cancer earlier, but also in developing new treatments and possible cures.
"We already knew which mutations cause cancer, but we wanted a model that would allow us to look for early detection of cancers," Schook said. Currently, if a patient is diagnosed with stage 3 or 4 of certain types of cancer, it is often too late for drug, radiation, or surgical interventions.
"If we could induce tumors in various tissues at very specific times, we could come up with early diagnoses and screening tools. That will allow us, if you have early onset cancer, to do something early on in the progression of the cancer. That's been our goal," he said.
Schook said the researchers are especially targeting cancers that are more difficult to diagnose in their early stages, including pancreatic, liver, lung, and bladder cancers.
"These are devastating diseases for which early detection is critical. If we could detect them earlier, we have ways to treat them," he said.
During a decade-long collaboration with Professor Christopher Counter at Duke University, Schook said researchers identified the pig as a better model than mice because of the pig's similarities in anatomy, size, metabolism, and genetics to humans.
Although the mice in their previous studies did develop tumors, the tumors were not similar to the tumors clinically observed in humans. Treatments, such as radiation or surgery, also are not scalable to mice.
"Many people who are diagnosed with liver, pancreatic, or lung cancer, for example, have either been smokers or drinkers, or are overweight, or have cardiovascular disease. These are comorbidities. With the pig model, we can induce comorbidities in pigs. We can induce tumors in tissue that would be very similar to clinical human tumors," Schook said.
Because of the ability to target individual locations, the model is applicable to a range of types of cancers.
"It also allows us to develop approaches to treating different cancers, depending on where they are located in the body," Schook explained. "We can begin to look at location and interventional radiology and microsurgery."
Along with strong the collaboration with Counter at Duke University, Schook said the University of Missouri's National Swine Resource and Research Center, supported by the National Institutes of Health, contributed to the project.
"We're excited that this pig is a national and international model that will be available to anybody doing research. They can get the model through the NSRRC," he said.
The study was recently published in the journal PLOS One.
Find out more about the "Oncopig" project on the University of Illinois website.
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