Embryologist teams up with ob-gyn professor to help young cancer patients preserve fertility

When Madison Erb chose fertility preservation as an academic discussion topic in her first year of the master’s program in the department of laboratory medicine (LMP), she had no idea it would launch her into a career shaping the future of fertility care in Canada.

Erb, who graduated in 2023, now works as an embryologist at Mount Sinai Fertility. As part of her work supporting people who want to conceive, she enables young cancer patients to preserve their chance of having biological children one day — through a groundbreaking procedure that, until recently, wasn’t available in Canada.

The technique, known as ovarian tissue cryopreservation, involves surgically removing, freezing and storing slices of ovarian tissue. Unlike egg-freezing, which requires weeks of hormonal stimulation and is not an option for children or patients requiring urgent cancer care, the procedure can be performed quickly — sometimes within days of a cancer diagnosis — and on patients as young as prepubescent girls. When the patient is ready to conceive, the tissue can be transplanted back, restoring fertility and hormone production.

“It’s a critical option for people facing treatments or conditions that could damage their ovaries,” Erb says. “And it’s been standard care in many countries for years — but not here.”

That reality began to change thanks to a chance connection during Erb’s presentation. Sitting in the audience that day was Jennia Michaeli, now a fertility specialist and assistant professor in the U of T departments of obstetrics and gynaecology and LMP.

Michaeli had worked with pioneers in ovarian tissue cryopreservation in her native Israel. She offered to supervise Erb’s Capstone research project, which focused on validating and refining laboratory techniques for the Canadian context. “At the time, we had nothing here — no equipment, no materials, not even tissue to work on,” she recalls. “Just the knowledge and the literature. We built everything from scratch.”

Their work helped lay the foundation for what has since become Canada’s first coordinated ovarian cryopreservation program — currently, services are offered pro bono at Mount Sinai Fertility while the team advocates for more sustainable provincial funding.

For paediatric and adolescent cancer patients, preserving fertility can offer hope at a time when families feel overwhelmed by a devastating diagnosis. “Many times, parents tell us that this is the brightest part of their journey,” Michaeli says. “It gives them something to look forward to, a sense of control.”

Worldwide, hundreds of babies have been born through this procedure over the last 20 years, but in Canada it was rarely offered, leaving families to travel abroad or forgo the chance altogether. “From the beginning, that was our motivation — to close that gap in care and bring Canada to the forefront of this practice,” Michaeli adds.

The lab work related to the procedure is intricate. Live ovarian tissue, removed during surgery, is sent directly to the embryology lab. There, Erb bisects the ovary and carefully trims it down to thin slices of the outer cortex, where the immature eggs reside. “The tissue has to be thin enough for the cryoprotectant solution to penetrate and to minimize the harmful effects of ice crystal formation,” Erb explains.

To ensure the eggs survive freezing, Erb’s Capstone research project validated a viability staining technique using neutral red dye in bovine tissue. “This step allows us to see under the microscope which oocytes (egg cells) are still alive after freezing and thawing,” she says as they look to transferring the technique to human tissue. 

Michaeli and Erb’s team now works with partners at The Hospital for Sick Children (SickKids), Princess Margaret Cancer Centre and Sunnybrook Health Sciences Centre, among others, to expand access to the procedure. Notably, at SickKids, a dedicated fertility preservation program has been established by Michaeli and  Sarah Alexander (Clinical Director of Haematology/Oncology and paediatric hemato-oncologist at SickKids), to raise awareness and create streamlined care pathways by integrating fertility discussions into cancer care. 

Through multidisciplinary collaborative efforts, Michaeli and Erb are facilitating the establishment of similar paediatric fertility preservation programs that are being launched in all paediatric oncology centres in Ontario. The unique ability to transport ovarian tissue from remote locations increases access to care across the province. The Children’s Hospital at London Health Sciences Centre is leading the way and has had several successful cases, with local tissue harvesting that was transported to the Mount Sinai Fertility Clinic for processing and storage. 

Erb is showing great potential to become a leader in the field and for Michaeli, that’s a testament to what the master’s in health science program in laboratory medicine is designed to achieve. “We’re not just training technicians,” she says. “We’re training scientists, leaders and innovators who can build fertility programs like this.”

For Erb, choosing ovarian cryopreservation as her first-year presentation topic shaped not just her research, but her entire career path. “It’s amazing to see how something I was so passionate about as a student has carried through,” she says. “Now, every day, I get to help patients and families during such a difficult time — and that makes the work incredibly meaningful.

This story has been adapted from LMP, with files by Matthew Tierney.