Some scientists have said the search for CTCs is like looking for a needle in a haystack. One millimeter of blood contains a few million white blood cells, around a billion red blood cells, and – perhaps – one to 10 circulating tumor cells. (illustration by Dan Cameron)
“You’ve got to respect the complexity of cancer,” Dario Marchetti, PhD, reminded researchers who gathered for his lecture at the Upstate Cancer Center recently. Marchetti is the director of the biomarker research program at the Institute for Academic Medicine at the Houston Methodist Research Institute.
Upstate frequently hosts guest speakers.
Marchetti spoke about efforts to detect the presence of circulating tumor cells, known as CTCs. These are cells that break off from a tumor and travel through the bloodstream. Most die in the blood, but some embed in tissues of distant organs, where they may form new tumors.
That’s what happens most often in the case of brain cancer. Marchetti says just one in 10 cases arise from a tumor that originated in the brain. The rest are cancers that spread from other parts of the body.
The Food and Drug Administration has approved one CTC test, CellSearch, which helps doctors monitor patients with metastatic breast, colorectal or prostate cancers by tracking the volume of CTCs in the blood. But it is not designed to find all CTCs.
Other methods of isolating CTCs are in development. Researchers want to be able to analyze CTC DNA to identify tumor progression and potential drug targets. That would allow doctors to determine the most effective medications without subjecting the patient to a tissue biopsy.
This article appears in the summer 2018 issue of Cancer Care magazine.