Glowing amino acid lights up growing brain cancer

Uptake of tagged glutamine allows scans to spot tumor changes during treatment

By injecting the amino acid glutamine that’s been tagged with a tracer compound into patients with brain cancer, scientists have devised a technique that might enable doctors to spot growth of such tumors with high accuracy.

Glutamine and glucose provide nourishment for malignant cells in patients with glioma, a cancer of glial cells. These support cells for neurons become ravenous for both nutrients when cancerous, so spotting their high uptake with brain scans could provide a way to monitor the cancer. But glucose is also taken up widely by normal tissues in the brain. In contrast, glutamine is voraciously gobbled up by several cancers including glioma, researchers report in the Feb. 11 Science Translational Medicine.

TELLTALE MARKER Tumor tissue (pointed out by the red arrows) shows up on this brain scan because the patient had received a compound that tags glutamine, an amino acid avidly taken up by active cancerous cells. Venneti et al/Science Translational Medicine 2015
Tests in mice with glioma show that a glutamine analog toting a telltale radioactive tracer gets taken up readily by glioma cells but not by healthy cells. The tracer shows up in PET, or positron emission tomography, scans. This allows tumor delineation, scientists from Memorial Sloan Kettering Cancer Center in New York City and elsewhere report.

In six glioma patients, brain scans revealed that while aggressive brain tumors took up the tagged glutamine readily, stable tumors did so only minimally, if at all. The imaging technique might enable doctors to more clearly track brain cancer growth, the authors say.

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