Studying the Seeds of Metastasis
What makes them dormant, and what makes them start to grow? And what makes them leave the prostate in the first place?
The first step to metastasis is for a few hardy cells to escape the main tumor and enter the bloodstream. These are circulating tumor cells, or CTCs. The bloodstream is a dangerous highway — think of the Autobahn — and not every cancer cell can survive it. But the toughest cancer cells manage to keep up with the traffic, exit the highway, and find a new place to live. These cells become “disseminated tumor cells,” or DTCs.
“Prostate cancer tends to metastasize to lymph nodes and bone marrow,” says oncologist Ken Pienta, M.D., the Donald S. Coffey Professor of Urology and Professor of Oncology and Pharmacology and Molecular Sciences. “These cells can remain dormant for a long time — years or even decades – before they begin to grow large enough to become detectable metastases.”
What makes them dormant, and what makes them start to grow? And what makes them leave the prostate in the first place? “We don’t know at what point during cancer development that these cancer cells escape the prostate and seed sites around the body,” says Pienta, who is the Brady’s Director of Research. He and his team have begun to try to understand the process of CTCs disseminating, and then of DTCs remaining dormant.
To do this, they have collected more than 255 blood and bone marrow samples from men undergoing a prostatectomy. “These samples were distributed throughout the country in a multi-institutional effort to understand how often and in what capacity these CTCs and DTCs could be detected with the most recent technology,” he explains. Of those samples, 45 bone marrow samples were processed in the Pienta Lab with a scanning microscope system that finds single cancer cells that would otherwise go undetected. “We hope to learn which men are at higher risk for recurrence after surgery, and who should have a more aggressive approach to treatment.”