Understanding Biomarkers in Brain Cancer

TL;DR

• Biomarkers are biological signals that reveal how a brain tumor behaves.
• They help guide diagnosis, prognosis, and treatment decisions.
• Many clinical trials now use biomarkers to match patients with targeted therapies.

Understanding Biomarkers in Brain Cancer

In brain cancer, not all tumors behave the same — even when they look similar on a scan. Two patients can receive the same diagnosis yet experience very different disease progression and treatment responses.

That's where biomarkers come in. Biomarkers are measurable biological signals found within a tumor that help doctors understand how the cancer grows, how aggressive it may be, and which treatments are most likely to work.

Rather than relying on imaging alone, biomarkers offer a deeper, molecular-level view of the tumor.

How Biomarkers Work

A biomarker can be a gene, protein, or specific mutation found in tumor tissue, blood, or other biological samples. These markers provide clues about the tumor's underlying biology.

Some biomarkers help confirm a diagnosis or refine tumor classification. Others are predictive, meaning they suggest how a tumor may respond to certain treatments.

For example:

• Certain biomarkers can indicate whether a tumor is more likely to respond to chemotherapy.
• Others may suggest sensitivity to immunotherapy or targeted drugs.
• Some markers help estimate prognosis, offering insight into how aggressively a tumor may behave over time.

Importantly, biomarkers do not treat cancer themselves. Instead, they guide clinical decisions, helping doctors move away from trial-and-error and toward more personalized care strategies.

Biomarkers in Brain Cancer Care

In brain cancer — especially glioblastoma — biomarkers play an increasingly important role. Tumors in the brain can be difficult to treat, and even small biological differences can significantly affect outcomes.

Several key biomarkers are commonly evaluated in glioblastoma, and are now standard parts of brain tumor pathology and treatment planning:

• MGMT promoter methylation: Helps predict whether a patient is more likely to benefit from temozolomide chemotherapy.
• IDH1 and IDH2 mutations: IDH-mutant tumors generally have a better prognosis than IDH–wild-type tumors.
• TERT promoter mutations: Very common in glioblastoma and often associated with increased tumor aggressiveness.

Patient-focused organizations like the Brain Tumor Foundation offer clear overviews of how biomarker testing is used in brain tumor diagnosis and care, helping patients better understand what these results mean in real-world treatment decisions. You can read more in their overview on brain tumor biomarker testing.

As research advances, more biomarkers continue to be identified — expanding the ways clinicians can tailor treatment plans and clinical trial options. Scientific reviews published in peer-reviewed journals, including comprehensive analyses of prognostic and predictive biomarkers in gliomas, continue to shape how these markers are used to guide therapy and clinical trial design. One detailed review is available through the National Institutes of Health's PubMed Central.

Exploring Biomarker-Based Trials With PACT AI

Today, many clinical trials use biomarkers to match patients with therapies designed for their tumor's unique biology. This approach — often called precision or personalized medicine — aims to improve outcomes by aligning treatment with what the tumor is most vulnerable to.

PACT AI helps patients and caregivers track these trials and understand which biomarkers matter for their diagnosis. By translating complex molecular information into clear, actionable insights, PACT AI supports more informed conversations and easier access to personalized treatment options in brain cancer care.

Learn more about how PACT AI can help →

Have questions? Reach out at contact@pact-ai.com.