Most of us have recently heard a great deal about how vaccines help protect against the serious effects of COVID-19. But did you know that vaccines can also be used to treat disease? One scientist and his team are developing a new vaccine as treatment for ovarian cancer.

This work leverages a strategic partnership between Ovarian Cancer Canada’s OvCAN research initiative and IRICoR, a leader in drug discovery. IRICoR is matching OvCAN’s funding dollar for dollar, helping research dollars go further faster. As a result, this is one of three projects being jointly funded.

“A strong immune system supports better health outcomes. We’ve seen this in scientific models, and other cancers,” explains Dr. Claude Perreault, Principal Investigator, Immunobiology Research Unit at IRIC; Professor, Faculty of Medicine, Université de Montréal. “When it comes to ovarian cancer, studies show that the more immune cells there are in a tumour, the better the prognosis.”

Dr. Claude Perreault

“These immune cells can actually help destroy cancer cells,” he continues. “So the question I am obsessed with is: how can we mount a stronger immune response, producing even more immune cells, to stop this disease?”

When functioning normally, immune cells react to foreign proteins, which are complex molecules made up of DNA that are not present at birth. Dr. Perreault led work to find the foreign proteins that were stimulating immune cells in different ovarian tumours. His team carefully examined portions of DNA that have known purposes – and found nothing.

“I was stunned. We knew immune cells were appearing in tumours because something was setting them off, we just didn’t know what it was,” recalls Dr. Perreault. “But in situations like these I always remember the words of the great detective Sherlock Holmes: Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth.”

His team reunited to work on what remained, large portions of tumour DNA that had no known purpose. It took lots of time and analysis. But they struck gold, finding a set of proteins capable of triggering an immune response in about 80 per cent of the ovarian tumours tested.

This knowledge is informing their work to develop a vaccine made up of messenger cells, technically referred to as “dendritic cells,” which interact with specific proteins to spur production of immune cells within ovarian tumours.

“This is the gold standard when it comes to triggering an immune response. We’ve loaded the vaccine with dendritic cells that can send signals to many different proteins found only in ovarian tumours. This casts a broad net to be effective in a wide variety of cases,” he says. “But all our studies so far have used scientific models and we will need to see whether the vaccine works in humans.”

Today, Dr. Perreault and his team are gathering evidence to support a clinical trial, where women living with ovarian cancer who meet specific criteria can volunteer to test the vaccine.

“Clinical trials are the truest test of whether an approach like this would be viable. Today we are doing everything possible to ensure all the checks and balances are in place to reach this crucial next phase,” says Dr. Perreault. “While we remain cautiously optimistic, based on our current data we have every reason to believe this will work and that we will be able to deliver on a new treatment option for women with ovarian cancer.”

Projects like this one are made possible by Ovarian Cancer Canada’s OvCAN research initiative, which is the result of advocacy efforts that successfully culminated in a historic $10 million investment in ovarian cancer research by the Government of Canada. To help ensure this work continues, please donate at

The views expressed herein do not necessarily represent the views of Health Canada.