Using Blood to Track Brain Cancer: What IDH1 Mutations Can Revea

Can a simple blood test tell us more about brain cancer? A study from researchers in Italy says yes—and it all comes down to a tiny but powerful mutation in a gene called IDH1.

Gliomas are a type of brain tumor, and diagnosing or tracking them usually means getting a tissue sample from the brain—an invasive and risky procedure. But what if we could just use blood?

That’s the idea behind liquid biopsy, a method that looks for cancer-related DNA floating in the bloodstream. It’s already used in some cancers like lung and breast. But brain tumors are tricky because the brain is protected by the blood-brain barrier, which makes it harder for tumor DNA to reach the blood.

A study set out to find whether a mutation called IDH1 p.R132H, commonly found in gliomas, could still be detected in blood—and whether that detection means anything for patient outcomes.

How the Study Worked

  • 67 glioma patients were included.

  • Researchers checked if the IDH1 mutation found in the tumor could also be seen in cfDNA (cell-free DNA) from blood samples.

  • They then looked at how this mutation related to overall survival—how long patients lived after diagnosis.

What Did They Find?

  • The IDH1 mutation was found in 31% of tumor samples and 22% of blood samples.

  • In 10 cases, the mutation appeared in both the tumor and the blood.

  • In some surprising cases, it appeared only in the blood and not in the tissue sample. This might be because the tumor was shedding DNA into the blood that wasn’t captured in the initial tissue biopsy.

Key result: Patients who had the IDH1 mutation—either in tissue or blood—lived significantly longer than those who didn’t.

  • Tissue mutation → median survival: 138.8 months

  • No mutation → 24.4 months

  • Blood mutation → 116.3 months

  • No blood mutation → 35.8 months

Even when the mutation was only in blood, patients still lived longer than average.

Why Does It Matter?

This tells us two big things:

  1. Liquid biopsy works—even for brain cancer. Despite the blood-brain barrier, researchers were able to detect important mutations through a simple blood test.

  2. The IDH1 mutation is a strong predictor of better outcomes. Detecting it through blood might help guide treatment plans, especially when surgery isn’t an option or when the tumor is hard to reach.

This approach still needs improvement—blood tests didn’t catch all mutations seen in tissue, and sensitivity was only moderate. But this research shows that liquid biopsy could become a helpful tool in managing brain cancer, especially for long-term monitoring and treatment personalization.

Want to learn more? Check this out!: https://bmccancer.biomedcentral.com/articles/10.1186/s12885-023-11726-0

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