Scorpion-derived 'tumor paint' helps canine veterinary patients at Washington State

One forward whip of a scorpion's tail delivers a sting that strikes like flame. It's ironic, then, that venom from a scorpion species known as the “deathstalker” is credited with prolonging the lives of a group of dogs, including three named Whiskey, Hot Rod and Browning.

At Washington State University, clinical trials of “tumor paint,” a product that lights up cancer cells, are proving beneficial in treating canines.

The reengineered molecule found in the venom of the deathstalker scorpion latches onto malignant tumors, making the diseased tissue glow brightly and distinctly against normal tissues. Consequently, surgeons are better able to detect and remove cancerous cells while leaving healthy ones behind.

Phase 1 of the trials involved administering tumor paint intravenously to 28 canine cancer patients prior to surgery, says William Dernell, DVM, MS, DACVS, professor and chair of WSU's veterinary clinical sciences, in a university release. “These were people's pets that had developed cancer spontaneously, not in a lab,” he says.

“The fluorescent substance prefers tumor cells over normal cells, allowing us to define the borders of where a tumor begins and where it ends,” Dernell says. “We're always hearing about some new compound that targets tumors. From what we've seen, this one really does.”

The approach is being used in people, too. Pediatric oncologist Jim Olson developed and patented tumor paint at Seattle's Fred Hutchinson Cancer Research Center as a way to help people, but also the pets they love, he says.

“Many animal tumors resemble those that arise in humans so it only makes sense for the two groups to reap the benefits that tumor paint can provide during cancer surgery,” he explained. “As WSU uses the technology to help dogs, the dogs provide information that's applicable to human cancers.”

Four years ago, Olson launched Blaze Bioscience as a way to test and commercialize the technology. Not long afterward, he contacted Dernell about conducting clinical trials at WSU. The results were so promising that the second phase will include feline patients as well, Dernell says.

“I predict that in a decade or so, surgeons will look back and say, ‘I can't believe we used to remove tumors by only using our eyes, fingers and experience,'” Olson says. “Those hidden deposits of 200 or so cancer cells? They won't go undetected.”