Scientist looks to beat cancer to the punch
By Paul Mayne
October 18, 2012
One of the biggest challenges in cancer treatment is tackling the spread of cancer (metastasis) as the disease becomes more difficult to treat once it spreads.
Through the use of powerful imaging techniques developed in her lab, Schulich School of Medicine & Dentistry professor Paula Foster hopes to determine how cancer cells change the tissue environment to which they migrate, before they arrive.
A $200,000 innovation grant from the Canadian Cancer Society will assist Foster in studying this corridor of cancer in hopes of understanding more about metastasis and, potentially, lead to the development of new therapies. She said it’s the spreading of the cancer that tends to overwhelm individuals, more so than the primary tumour.
“An old, old theory that my research is based on, which is called the ‘seed-and-soil’ hypothesis, says there’s a propensity for cancer to spread to certain organs,” she said. “Breast cancer won’t spread to every organ. It likes to go to the bone. It has something to do with there’s calcium in the bone and calcium in the breast. That environment is suitable for it to grow in.
“Some organs are more suitable for certain cancers to grow in, which leads to the concept which I’m working with and that is a pre-metastic niche,” Foster continued. “Let’s say breast cancer, for example, and it’s going to metastasize to the brain, the cells go to the brain and start getting the tissue ready. What they do is secrete different factors that change the vessels so cells can get in easier; they start to recruit other cells and make a nice place for cancer to live.”
In her research, Foster is concentrating on breast cancer and brain metastasis. If diagnosed with metastic breast cancer, 20-40 per cent of patients will suffer a brain metastasis, with the diagnosis often being just months.
Foster has no preliminary data yet, given the newness of this area. This will now change, thanks to her funding. It also allows her the opportunity to use the imaging tool she has developed called ‘Cellular MRI,’ which loads cancer cells with iron nano-particles, allowing her to see them with the MRI - to the point of detecting a single cell in the brain of a mouse.
Admittedly a “very challenging area to work in,” Foster’s creative approach of looking at cancer cells’ new destinations, rather than the initial tumour, could change the current understanding of metastasis.
In her work, mice are injected with cancer cells, with a percentage of these cells growing in certain tissues without the primary tumour ever existing.
“That’s why I hypothesized that maybe just individual cancer cells themselves, after they arrive in a tissue, can start to create that environment, so it’s not necessarily the primary tumour that’s doing it,” she said.
There are a number of cases where an undiagnosed primary tumour isn’t found until after it spreads elsewhere. Studies are now showing the spread of cancer cells from a primary tumour is an early-on incident, not the late-in-the-game event many tend to think.
“People who have a primary tumour and have it treated successfully, sometimes find they have an occurrence months or years later, and that’s often because of metastasis,” she said. “The spread is early, but they just sit there and do not grow. The fact the cancer cells spread early means we have to understand what they’re doing in those tissues to better understand how to treat it.”
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