Targeting breast cancer
University of Calgary researchers are expanding the understanding of breast cancer and devising new treatments in the fight against this deadly disease.
Learning the 'language' of breast cancer
University of Calgary researcher Carrie Shemanko, PhD, is trying to figure out how the biochemical machinery in cells that normally helps the body can also feed the spread of tumours that do the exact opposite.
“Breast cancer will spread in about 20 per cent of women," Shemanko says. "In the majority of times when that occurs, the cancer cells spread to the bone — and when they do, those cancer cells can speak the same molecular ‘language’ as the bone cells and induce their specialization, essentially breaking down the bone."
“This in turn feeds the cancer cells and will lead to more tumour formation inside the bones, causing them to become weaker and to possibly break. It can also cause a lot of pain, so we’re trying to learn that language that the cancer cells speak to the bones so that we can disrupt it.”
People who survive the initial breast cancer can end up dying from its spread to their bones, says Shemanko, who is an associate professor in the department of biological sciences in the Faculty of Science and a member of the Arnie Charbonneau Cancer Institute at the Cumming School of Medicine.
“I’ve had a number of family members that have been affected by breast cancer and other cancers, and I’ve lost family members,” she says. “I think this is something that we all share — that we are all touched by cancer in some form or other.”
As a scientist, Shemanko sees breast cancer as a way to learn more about how the human body works so she can help patients. Her research team has found that a hormone called prolactin, which is part of normal breast development and milk production, can instead accelerate the ability of the breast cancer cells to break down bones.
“It shows how the cells of a completely different organ can communicate with the cells of another organ, and understand each other and control each other,” she says. “Breast cells are not normally close enough to the bone to ever have any impact, but when the breast cancer cells spread, they are able to manipulate their new surroundings to their own advantage.”
The discovery of prolactin’s role opens up the possibility that a way can be found to disrupt bone weakening, says Shemanko. “We’re trying to identify drugs that will prevent that process.”
But other factors in the disease are currently unknown, she says. “Sometimes, these breast cancer cells live in the bone in a state of dormancy for years or decades, and then at some point, they become activated and can actually start growing,” she says. “We don’t understand what causes that.”
Things to remember
- When breast cancer spreads, it travels to the bone in the majority of cases.
- When it spreads to the bone, it is still breast cancer, not bone cancer.
- Breast cancer cells that traveled to the bone can communicate to certain bone cells, causing them to increase their normal function and break down bone.
- The breakdown of bone feeds the breast cancer cells that are living in the bone.
- Understanding the language used in this communication of breast cancer cells with bone is a step toward being able to interrupt that conversation with drugs.
Seeding a treatment for breast cancer
As a PhD student in the department of physics and astronomy in the Faculty of Science, Elizabeth Watt is focusing her research here on Earth. She is studying how a treatment involving small radioactive pellets can be improved to better help breast cancer patients across Canada.
“It is called permanent breast seed implant,” says Watt. “It’s a one-day outpatient procedure, so women can come in and have the seeds implanted under general anaesthetic.”
The size of a grain of rice, each of the seeds contains an isotope called palladium 103 that emits X-rays over a very short distance for about six months, she says. The implants are coated in titanium, which is highly resistant to heat and corrosion and doesn’t react with the body.
The seeds are closely placed around the cavity remaining after the tumour is removed, says Watt. The treatment is aimed at women aged 50 and over, offering a way to focus radiation solely on a target while limiting the damage to healthy tissue, she says.
Standard methods expose the entire breast to radiation and involve several radiation fractions, she says. The pellets constantly focus X-rays on the target in many directions, delivering the prescribed dose in about six months and remain permanently in the breast, says Watt.
“It would be very challenging to the patient to remove them, and because all the materials are inert to the body, there is really no reason to remove them,” she says. “The patient can sometimes feel them, particularly if they’re close to the skin, but in general, they shouldn’t cause a large impact on the patient’s life.”
As part of the graduate program in radiation oncology physics, Watt wants to use her background in engineering and science to help people suffering from cancer. “My dad had prostate cancer over 10 years ago, but he was treated and has been cancer-free,” she says.
“He was lucky. His cancer was caught extremely early, but I think it was definitely a mental scare for him to be diagnosed with cancer when he was under the age of 50 and very healthy.”
Permanent breast seed implant, which was first performed in Canada in 2004, is based on a similar treatment for prostate cancer, she says. Watt’s thesis for her PhD will look at how to better assess the placement and effectiveness of the implants for breast cancer patients, ensuring the treatment they receive at each clinic across the country is standardized to the best possible level.
“I tend to split it in terms of the radiation dose, so I’m looking at how and where the radiation is deposited by the seeds,” she says. “The other side looks at the mechanical traits of the implants. It involves about 70 seeds being inserted by about 15 needles, so I’m looking at things like, ‘Were they inserted parallel to each other, and did they go to the depth we were hoping for?’ It’s about helping to learn new ways to make sure the implants are done as accurately as possible.”
Watt is working on a computer algorithm or program that will do “any manual analysis of the implants completely automatically,” she says. “It will match the planned seed positions with where they ultimately ended up.”
As a University of Calgary student, she says she is lucky to be part of a team doing research at the Tom Baker Cancer Centre at the Foothills Medical Centre, including researchers affiliated with the Cumming School of Medicine on the university’s Foothills campus. “It’s very exciting, to be honest, to be in a place with so much research to do and so many things that could immediately make an impact in a patient’s treatment,” she says.
“I’ve had the opportunity to work with a multi-disciplinary team here with our radiation oncologist, treatment planners and radiation therapists. I’ve really had all their support as we’ve tried to answer some of these questions to ultimately treat our patients better.”
Things to remember
- Permanent breast seed implant is an innovative treatment technique for early-stage breast cancer patients.
- Small radioactive "seeds" are implanted in the breast and remain in the patient's body forever.
- This technique was inspired by a similar procedure that has been used for decades in the treatment of prostate cancer.
- Ongoing research looks to improve and automate the analysis process for this technique to provide feedback to the oncologist and to facilitate the inclusion of this analysis into clinical practice.
Carrie Shemanko is an associate professor in the department of biological sciences in the Faculty of Science and an associate member of the Arnie Charbonneau Cancer Institute at the Cumming School of Medicine. Her research focuses on the molecular signalling pathways that contribute to mammary gland development and breast cancer, in particular the prolactin pathway. View Carrie's publications