Alberta Cancer Foundation

Dr. Gilbert Bigras’ True Calling as a Pathologist

Dr. Gilbert Bigras works closely with his team in the IHC lab at the Cross Cancer Institute.
Photograph by Cooper & O’Hara.

When Dr. Gilbert Bigras tells people he is a pathologist, the most common response is, “Oh, so you do autopsies.” Call it the CSI effect (after the popular television crime drama), but the work of a pathologist is often misunderstood.

Of course, some pathologists do conduct autopsies. But most of them, Bigras included, examine live tissue samples to provide the best possible diagnosis, which is then used by clinicians to create a patient’s treatment plan.

“We have way more work to do with living patients than with the dead,” Bigras says with a chuckle. As the medical lead of the Edmonton Zone Immunohistochemistry (IHC) Laboratory for Alberta Health Services, he examines and diagnoses tissue specimens while also overseeing the largest lab of its kind in Canada.

Though they may never meet him during the course of their cancer treatment, the work of Bigras and his team (and that of his fellow pathologists) aids in the diagnosis and treatment of thousands of patients each year.

“People will say, ‘My doctor told me I don’t have cancer,’” Bigras says. “Well, it’s not their doctor. It’s the doctor behind their doctor. That’s us, providing direction for the patient.”

Here’s what happens behind the scenes: After a patient receives a biopsy or surgery, a whole piece of tissue or smaller sample is fixed in formalin, then encased in a paraffin wax cube. That cube is then sent to a lab to be made into slides. The pathologist will then use his or her microscope to inspect the tissue and determine if there is any anomaly. At this point, the pathologist might need additional information from the tissue, and that’s where the IHC lab comes in.

When needed, additional thin sections from the same wax cube are obtained, baked and sent to the Edmonton Zone IHC lab (currently located in the Cross Cancer Institute). Next, the IHC lab technologist uses specialized machines to perform antigen retrieval, a process that uses heat and buffers to prepare the section for the next step: immunostaining.

During immunostaining, the machine applies highly specific antibodies, which target and link to specific proteins within the patient’s sample. If the proteins are present, they will be revealed by stains linked to the applied antibodies.

This additional information allows the pathologist to reassess the tissue and improves the diagnosis process. It might also predict if the patient would respond to a specific drug. The pathologist then sends his or her diagnosis to the clinician, perhaps an oncologist or a surgeon, who determines treatment.

For Bigras, balancing work as the lone pathologist in the IHC lab, while also administering that lab and finding time for his own research interests, is no small task. He manages his multiple obligations with a team-first approach. He works closely with Sarah Canil, the IHC laboratory scientist, as well as nine other lab technologists and a lab manager, to troubleshoot issues as they arise.

“I’m a medical resource, on the spot to help for any kind of problems related to immunohistochemistry,” says Bigras.

Photograph by Cooper & O’Hara.

Lab staff members appreciate his open-door policy. “He’s so easygoing and so approachable,” says Canil. “He’s not going to tell you, ‘You have to go do this.’ Instead, he’s going to ask for opinions.”

Bigras’s sense of humour is also widely appreciated among his co-workers. A Francophone who grew up in Quebec, he readily pokes fun at what he sees as his tenuous grasp of English — like the time he thought the idiom “even keel” was “even kill.” In fact, when Bigras was being recruited by DynaLIFE Medical Labs for his first Edmonton pathologist position back in 2004, he initially refused the offer.

“They asked me over the phone if I was interested, and I said, ‘You should find someone who speaks better English than I.’”

After more consideration, however, Bigras, who was working in Geneva, Switzerland, at the time, accepted the job, and he moved to St. Albert with his wife, Nicole, and their twin daughters to begin a new stage in his professional journey.

Bigras’s career path is a winding one. From the time he was a five-year-old boy, he wanted to be a surgeon, and he got pretty close to that childhood dream in the 1980s during his medical studies at the University of Montreal.

“I started some training in surgery,” Bigras says. “But, after a year, I discovered it was not for me. No regret.”

He had a passion for computer science and image analysis, so he started a master’s degree in biomedical engineering related to computer science. He wasn’t ready to throw out his medical studies, however, and pathology seemed like a perfect fit — it allowed him to combine image analysis with medicine.

From there, Bigras finished his post-graduate studies, earning a PhD in biomedical engineering in France in 1997 before returning to Quebec to work as a pathologist.

“I found my job very tough,” he recalls of those days in Quebec. “We were missing Europe.” So, it was back to Europe for a position as a pathologist in Switzerland. The need to be closer to family brought Bigras back to Canada in 2004, and he has been the medical lead of the Edmonton Zone IHC lab since 2012.

In his research, Bigras finds ways to combine pathology with his passion for computer science and image analysis. Recently, he partnered with Nilnanjan Ray, an associate professor in the Department of Computer Science at the University of Alberta, to explore algorithms related to artificial intelligence. He’s also excited to work with Ray and other U of A computer scientists on projects using convolutional neural networks (CNNs), a hot field of research embraced by companies including Facebook and Amazon. CNNs, which essentially help computers identify and classify IHC images, could someday be used to aid in cancer diagnosis by classifying the samples that pathologists currently view under a microscope.

“It’s very exciting,” Bigras says.

Another exciting and rapidly evolving field for pathologists is testing for biomarkers, which doctors use to predict how well a patient will respond to particular treatments. The IHC lab is working with an Edmonton Zone molecular pathology lab run by Dr. Iyare Izevbaye to become a centre of excellence in this field, especially when it comes to testing for certain lung-cancer biomarkers required for immunotherapy.

“It has been a dream, for decades, that our own body should be able to get rid of a cancer by using our own immune system,” says Bigras. “Like with a cold — we get rid of the virus with our own immune system.”

As he explains, cancer cells usually present a molecular signal to immune cells that say, “Go away, I’m your friend.” But new drug therapies developed in the last few years can inhibit the signal, allowing a patient’s own body to destroy cancer cells. The administration of the drug can translate to an efficient treatment for some lung-cancer patients who would otherwise have a terminal diagnosis.

“Even though their prognosis was dismal before, some of these patients are probably cured,” says Bigras. “This is spectacular!”

Not all patients respond to treatment, but the field of immunotherapy is still in its infancy. Under Bigras’s leadership, the IHC lab also looks for a lung biomarker called PDL1 in patients throughout Alberta and Saskatchewan. In 2017, the lab performed the lung cancer biomarker test for more than 1,600 patients.

The IHC lab also tests for breast cancer biomarkers, which can be used to determine which treatment is the most appropriate.

While biomarker testing represents only a small fraction of the tests currently conducted in the Edmonton Zone IHC lab, Bigras sees this as an area of medicine that will only be expanded in the near future, as all facets of cancer care strive for a personalized medicine approach.

“Pathology is entering a new world,” says Bigras. “The pathologist will be involved more and more to provide new types of information, beyond the simple diagnosis of cancer. We will provide information that will drive the treatment.”

Pathology Work in Edmonton, by the Numbers

Approximate number of anatomic pathologists in Edmonton

Lab assistants working in labs in the Edmonton area

Number of IHC tests conducted in the Edmonton Zone IHC lab each year

Unstained slides lab technologists can slice off one biopsy cube 4 Main types of breast cancer classified by biomarkers