Finding Points to Possible Blood Test for Br...( Tiny sacs released by glioblastoma ce...),Health

Tiny sacs, released by glioblastoma cells, can be detected, study shows

MONDAY, Nov. 17 (HealthDay News) -- Researchers have stumbled across a novel mechanism by which brain tumors model their environment to nurture their own growth.

The findings expose a fundamental biological process of which oncologists were previously unaware, and which may one day be exploited to combat glioblastoma, experts said. But just as significantly, they provide a potential means to monitor cancer progression and treatment by a simple blood test, rather than having to rely on either brain imaging or biopsies -- something that currently is not possible.

"Wouldn't it be awesome to know that a tumor is not fully treated or recurring before you ever see it on an X-ray or an MRI?" mused Dr. Paul Graham Fisher, a neuro-oncologist at Stanford University. "Or even beyond that, I mean, this gets way down the road, could you do a blood test to detect a brain tumor? That would be just awesome."

In findings reported in the Nov. 16 issue of Nature Cell Biology, Xandra Breakefield of Massachusetts General Hospital, and her team, led by Johan Skog, report that glioblastoma cells secrete small membrane-enclosed sacs called microvesicles. Filled with proteins and genetic material, these vesicles are picked up by neighboring cells in the brain, where they apparently induce them to alter their gene expression program to suit the needs of the tumor. Specifically, these cells can be coaxed into forming new blood vessels to supply nutrients to the growing cancer mass.

"We think the tumor cells bud off these vesicles filled with information, genetic and protein information, to actually take over their environment," said Breakefield. "I mean, they are doing it for a purpose, and they're doing it with a vengeance."

In fact, the tumors secrete so many of these vesicles that they can be found in the patient's bloodstream, outside the
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