In early January 2019, a 20-year-old former Purdue student and cancer survivor named Tyler Trent lost his years-long battle with osteosarcoma. Three times he faced the disease head-on fighting to the end with the determination of a champion. A devoted fan of his university’s football team, the Purdue Boilermakers, Tyler was honored with touching tributes from players, coaches, and other students
As his oncologists explained to the Indy Star, Trent had developed a secondary tumor in his pelvis, an aggressive form of bone cancer. After the tumor was removed in early December 2018, Tyler chose to donate his own tumor cells at the tumor biobank at Riley Children’s Hospital at Indiana University Health. Some of those cells were implanted in mice so researchers would be able to better understand osteosarcoma, how it develops, and hopefully find a future cure. He was so excited about the process that he was invited to name two of the cells – TT1 and TT2.
“I feel like I’m getting to view my legacy come to life,” Trent told the Indy Star via text message. “I’m incredibly thankful that I’m getting to see the impact tissue donation is having. Most people don’t live long enough to see their impact but I’m getting blessed with that.”
By donating tumors to bio-banks, for use in scientific and medical research, patients can help strengthen the body of knowledge about the molecular mechanisms of cancer while facilitating the development of new treatments.
For decades, cancer has ranked second among the leading causes of death in the United States — one of every three people will develop the disease and one of every five will die from it.
Enter Precision Medicine
Among the many new and emerging technologies of the 21st century, is an exciting frontier in science and medicine that could drastically lower the number of people (and animals, too!) that will succumb to cancer: precision medicine.
Broadly, the term refers to the development of treatments tailored to the individual characteristics of the patient. It’s an approach by which researchers are looking for new, better cancer medicines that are most effective in treating specific sub-types of people.
Cancer treatments have come a long way. But oncology researchers have struggled to understand why many cancer patients, like Trent, go into remission after treatment only to then develop secondary tumors, which are often more aggressive.
With tumor biobanks and precision medicine, it is now possible to study relapse tumors in animal models to better understand how the disease metastasizes and to look for vulnerabilities that could open the door to new therapies and treatments.
The process works by taking tumors that have been excised from human patients (“patient-derived xenografts,” or PDX) and implanting them into the animals. Just as transplant recipients must take medication to suppress their immune systems to prevent organ rejection, these models are bred to be immunosuppressed. Then, as the tumor grows naturally, researchers can gauge the cancers’ response to any one, or a combination of, different chemotherapies, drugs, and other treatments.
“PDX models have been successfully established for breast, prostate, pancreas, colorectal, lung, and many other cancers,” explained the authors of a 2017 study in Cancer Research and Treatment. “They are used for drug safety and efficacy studies as well as examining personalized response to certain anti-cancer agents.”
Researchers are generally loathe to over-hype their findings, but the discovery that so-called in-vivo PDX models can lead to cancer drug discovery is significant. Or, in the parlance typical of scientific journals, the PDX model is “becoming a preferred preclinical tool in drug development [and] is regarded as a useful tool to apply the personalized medicine.”
All cancer patients will benefit from new and superior treatments, but the advantageousness of PDX models in drug discovery, via research with animals, offers hope for people with rare and difficult-to-treat cancers.
Some patients who have undergone chemotherapy and are in remission can develop a secondary type of cancer in the breast—“triple-negative,”—which is so-named because the three receptors known to fuel most breast tumor growth are absent in this form of the disease. Most treatments work by targeting the receptors, and therefore they are ineffective in patients diagnosed with this variant of breast cancer.
It happens that patient-derived triple-negative xenografts have a much higher success rate than xenografts of other breast cancer tumors, meaning researchers can effectively study the disease in animal models to look for an effective treatment.
Precision medicine in biomedical research has produced exciting and promising discoveries so far. This is just the beginning, and with the continued help of animal research and patients like Tyler Trent, the future looks brighter each day.
At Tyler’s funeral — attended by thousands including the entire Boilermakers football team, the governor of Indiana, and CBS and ESPN sportscasters – one of the recurring themes was his devotion to finding a cancer cure.
The college football superfan who dreamt of becoming a sports journalist was not only an inspiration to his immediate community, but inspired millions around the country generating awareness for cancer research.
Trent once said that he wanted to leave his mark in the world. With his positive spirit and selfless donation to research, he surely did.
by: Christopher Kane and Crister DelaCruz
photo: Purdue Athletics