Cancer and Evolution: Two Sides of the Same DNA Coin

When he started his career decades ago, he explained, “We knew nothing about mutations that cause cancer. Now, we are unmasking cancers one at a time, and cures are certain to follow.”

A Devastating Pediatric Cancer

Alexandra Callan, MD, an orthopedic oncologist at the University of Texas Southwestern Medical Center, told the story of Isabelle “Izzy” Martin, a young patient. Izzy valiantly fought osteosarcoma for over two years before passing away this July at age 12. Dr. Callan said that Izzy made “a greater impact on my career and in the fight for osteosarcoma than any other human.”

“She raised nearly a half a million dollars for osteosarcoma research, and she touched the hearts and the lives of children and other families across the world,” said Dr. Callan.

Learning from Man’s Best Friend

Veterinary oncologist Chand Khanna, DVM, PhD, spoke on unique features of osteosarcoma’s development as seen in his canine patients. His work with Irish Wolf Hounds and Great Danes demonstrates that osteosarcoma tends to occur in the long bones of the body, where bone growth is rapid. Dr. Khanna also noted that since the advent of chemotherapy in 1986, there have been no other significant improvements in osteosarcoma treatment. Research is needed, Dr. Khanna said, “to understand how these genes that cause or allow evolution [also] cause cancer.”

A Deep Evolutionary History

David Evans, PhD, oversees dinosaur research at the Royal Ontario Museum at the University of Toronto. He described his team’s work diagnosing osteosarcoma in the shin bone of a 77-million-year-old Centrosaurus, a cousin of the Triceratops. The discovery, announced in 2020, was the first confirmed case of an aggressive cancer in a dinosaur.

Dr. Evans said, “The finding in a dinosaur suggests that bone cancer has a very deep evolutionary history going back to the shared common ancestor of humans and dinosaurs.” He noted that the development of the cancer matched what is seen in human cases today, “appearing in the knee end of a lower limb bone.”

Understanding Cancer’s Growth

Paul Meltzer, MD, PhD, chief of the genetics branch at the National Cancer Institute, provided a genetic perspective on what causes osteosarcoma and its development.

He explained that the cancer normally begins with “a mutation in one cell in growing bone that destroys a single gene” that maintains the integrity of the genome. Without that crucial gene, known as P53, the cancer multiplies. Dr. Meltzer highlighted a challenge in treatment: “No two patients’ osteosarcomas have identical changes in their genomes.” However, cancer researchers are starting to discover the underlying rules that govern cancer’s growth, which may unlock new treatment options.

Making Cancer Extinct

The final panelist, Damon Reed, MD, a pediatric oncologist and clinical co-leader of the Evolutionary Therapy Center of Excellence at Moffitt Cancer Center, called cancer “our most personal experience with evolution.” Every time cancer starts as one cell and mutates, it is as if a new species is created.

“As opposed to all the efforts you have heard where we do not want to make more animals extinct, cancer therapy is trying to make this new species go extinct,” he said. “We are trying to cause extinction.”

The current approach to cancer treatment lets cancer take the lead. “We then try to catch up,” Dr. Reed said. A more proactive approach should anticipate the cancer’s resistance to treatment.

To an audience question on whether osteosarcoma is more prevalent now than in the past, Dr. Callan said that there are approximately 1,000 new diagnoses per year in the United States, but that number is steady.

“We’re not seeing an increased incidence,” she said. “It’s just bad luck.”

The lively conversation continued at the reception, allowing audience members to speak directly with panelists about these potential avenues to tackling osteosarcoma.