For most scientists, there’s nothing like that elusive ‘aha’ moment of discovery. For Dr. Gang Zheng, now the associate research director at the Princess Margaret Cancer Centre in Toronto, that moment came in 2011. He unexpectedly discovered a new class of tiny particles that could harness the power of light to improve how cancers are diagnosed and treated.
He called these nanoparticles porphysomes and has been working to perfect them ever since.
“I knew it was a gamechanger right away,” he remembers. So did the scientific community. When the research was published in the respected peer-reviewed journal, Nature Materials, it was cited as one of the top 10 cancer breakthroughs of 2011.
Fast-forward to 2025. After years of tweaking and testing, Dr. Zheng and his team are set to start the first human clinical trials with porphysomes next month. It’s more than an ‘aha’ moment. It’s a giant leap forward for Dr. Zheng and project co-leads Drs. Jonathan Irish and Brian C. Wilson – and potentially for cancer patients across Canada and beyond.
The long road from bench to bedside
The path to discovery is rarely direct. It takes years for breakthroughs in the lab to benefit patients in the clinic.
Porphysomes are a powerful example of what we can achieve when we support brilliant scientists with sustained funding and a long-range vision. Porphysomes are natural, non-toxic particles that respond to light and oxygen. When injected into the body, they accumulate in cancer cells and can be used to target and kill those cells.
Using multiple imaging techniques, such as a PET scan or a fluorescence camera, clinicians can see the porphysomes within the tumours. These images can help guide surgeons to a tumour that might otherwise be missed. Porphysome-laden tumours can also be destroyed with heat or light, typically delivered via a laser. And oncologists can use these tiny assistants to track residual cancer cells in the body after surgery.
Dr. Zheng recognized their potential immediately. And in 2013, the research team applied for and received a Terry Fox New Frontiers Program Project Grant from the Terry Fox Research Institute (TFRI). In the years since, the team has continued to unlock the potential of porphysomes with the support of TFRI and donors to the Terry Fox Foundation.
“Sustained funding has enabled this entire bench-to-bedside journey,” says Dr. Zheng. In all, the team has received three multi-year grants from TFRI totalling nearly $15 million – a very rare achievement. Their most recent grant secures their funding until 2029.
Demand for TFRI funds is intense. And applicants’ proposals are subject to a rigorous review process conducted by an international panel of referees. When Drs. Wilson and Zheng received the first TFRI award, it became a proof-point for other funding organizations, enabling the team to secure even more financial support.
Dr. Zheng points out that many awards don’t support research that falls into ‘the gap’ between discoveries. But that’s often the staging area for the next breakthrough. “TFRI doesn’t follow trends, they create them. And they believed in our vision,” he says.
What’s the team’s end goal? They’ve already demonstrated that porphysomes can target cancer cells in experimental models of gynecological, head and neck, pancreas, lung, brain, prostate, and colorectal cancers. “With our most recent award, we’re looking at how porphysomes might be used to ‘hijack’ the body’s own immune system to potentially limit the spread of the disease.”
It’s incredible to realize that this transformative 13-year project started with an idea; with TFRI’s big picture perspective; and with the support of donors to the Terry Fox Foundation.
“It’s a pure Canadian discovery,” says Dr. Zheng with pride.
Learn more: tfri.ca.
