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Cyrus ghajar, phd
Cyrus ghajar, phd
Cancer Researcher and Outdoor Enthusiast
Cancer Researcher and Outdoor Enthusiast
About cyrus
About cyrus
Dr. Cyrus Ghajar is a faculty member at the Fred Hutchinson Cancer Research Center in Seattle. Cyrus grew up in the San Francisco Bay Area, where he used to love playing all kinds of sports when he was young. He moved to Seattle with his wife and two young boys, Owen and Grayson, several years ago. In the meantime, they’ve added a daughter, Ava, to their family. Their favorite things to do as a family are to go hiking and kayaking (in the summer, not the winter).
Cyrus got into science because he loved getting to satisfy his curiosities doing something that could help people in need. His favorite thing about his job is that on any given day, he may see something no one has ever seen (or appreciated) before.
Image courtesy of FHCRC
What does Cyrus study?
What does Cyrus study?
Cyrus directs a lab at Fred Hutch that studies breast cancer metastasis. Metastasis is when cancer cells from a breast cancer tumor travel to an adjacent organ, or to a more distant part of the body through the bloodstream. Cyrus and his team study metastasis by observing how tumor cells behave in other organisms like mice and zebrafish, or in cultures of human cells that are created in the laboratory. Unfortunately, it’s difficult to tell when and where a metastasis will occur, so there's really no way of preventing metastasis yet. Often, a metastasis can happen shortly after the initial tumor has been removed (within months). However, some metastases (plural of metastasis) happen years or even decades after the initial cancer is removed. Metastases form from something called a “disseminated tumor cell” (DTC)--a cell that has been sent from a tumor to a different part of the body. These DTCs can stay dormant, or inactive, for many years until they “wake up” and grow into a tumor.
Two big questions in Cyrus’ field of research are:
Two big questions in Cyrus’ field of research are:
1) How are disseminated tumor cells kept dormant, and,
2) Why do they wake up?
In his words...
In his words...
"Why not find a way to make therapy…more effective? We want to prevent [patients] from looking over their shoulder in five or 10 years, wondering if the cancer’s going to come back."
Cyrus' Research
Cyrus' Research
To answer his questions about disseminated tumor cells, Cyrus and his team first had to find out where exactly the DTCs go in the body. By studying tumors in mice, they found that they live on something called endothelial cells, which make up the tissue that lines blood vessels. Specifically, they found them on the outside (called the abluminal or basal surface, as opposed to the luminal surface, which is the inside of the tube) of tiny blood vessels in the lungs and bone marrow. They found that these endothelial cells can make DTCs go dormant and keep them that way using a molecule called thrombospondin-1, a protein that is made naturally by the body and that plays a role in tumor suppression (keeping individual tumor cells from turning into full-blown tumors). After figuring out where breast cancer DTCs go and how the body keeps them dormant, Cyrus’ next step was to find out why they wake up.
Breast cancer brain metastasis (red) growing along blood vessels (green).
Image courtesy of FHCRC
Image courtesy of FHCRC
Breast cancer lesion in lung (green) surrounded by CD8+ T cells (cyan).
Image courtesy of FHCRC
Image courtesy of FHCRC
He found that it has to do with something called neovascularization (knee-oh-vas-cue-lar-eye-zay-shun). This is the name for the body creating new blood vessels. This can happen if tissue isn’t getting enough blood flow--either due to trauma/injury, disease, or blockage of existing vessels. Cyrus found that when new vessels were forming, the tips of the new vessels not only ended the dormancy of the DTCs, they actually promoted tumor growth. These findings are important because they shed light on a few different ways that doctors could potentially keep cancer survivors’ DTCs from waking up, or stop tumor formation once they do wake up (causing their cancer to come back). One option would be to avoid neovascularization altogether, which seems to be a wake up alarm for DTCs (there are a few known medicines that can do this). Another way would be to treat cancer survivors with thrombospondin-1, which this study suggests helps keep the DTCs “asleep”. This study also helped show specific molecules that help the tumors grow after neovascularization, so it could be possible to target those, as well.
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