A gene change in a brain tumor that a blood test did not find
Original title: ESR1 Y537S Detected in a Brain Metastasis but Not in Plasma ctDNA in HR+/HER2-Low Metastatic Breast Cancer: A Case Report.
How far along is this research?
- Lab cells
- Animals
- Review
- Tested in people
This was tested in people. That is the most reliable kind of research we share.
This is a report on one patient, not a treatment tested in a trial.
The short version
In one woman, a blood test missed a gene change that her brain tumor had.
What was studied. Doctors report on one woman, age 60, with breast cancer that had spread. Her cancer grew in her brain, and surgeons removed a large tumor there.
What they found. Tests on the removed brain tumor found two gene changes. A blood test done after surgery found no cancer gene changes at all. Her cancer outside the brain was still under control at the time.
What this means, and what it doesn't
What it could mean: A blood test may miss gene changes when cancer is growing only in the brain. If a brain tumor is taken out, testing that tissue can tell a doctor more.
What it doesn't mean: This is one person's story, not a study of many people. It does not test a new drug, and it is not a cure. It does not prove that blood tests fail for everyone. Larger studies would be needed before this changes everyday care.
Source: PubMed, July 28, 2026 · Read the original
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