Bladder Cancer Biomarkers
FGFR3 mutation testing is the most important new biomarker in bladder cancer — if your tumor carries this mutation, the targeted drug erdafitinib may be an FDA-approved option.
Reviewed by XpertPatient Medical Advisory · Updated June 2026 · Sources: NCI · ACS · ASCO · NIH/PMC
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What is a biomarker?
A biomarker is a measurable signal in your tumor tissue or blood. In bladder cancer, biomarker testing looks for specific gene changes that can be targeted with newer drugs.
Until recently, most people with advanced bladder cancer had only one option: chemotherapy. Biomarker testing has changed that. Knowing your tumor’s specific mutations can open the door to targeted drugs and immunotherapy that work differently — and sometimes better.
What this means for you: The key question for bladder cancer biomarkers: does your tumor have a mutation that a targeted drug can block, or a marker that suggests immunotherapy will help?
The Tests Your Doctor Orders
🔍 Does your cancer have a gene change that a targeted drug can block?
FGFR3 mutations are found in 15–20% of advanced bladder cancers. If you have one, erdafitinib (Balversa) — the first targeted drug specifically approved for bladder cancer — may be an option for you.
🔍 Can immunotherapy help your immune system attack the cancer?
PD-L1 testing helps your doctor decide whether immunotherapy drugs like pembrolizumab or atezolizumab are likely to work. Higher PD-L1 levels are associated with better immunotherapy response.
🔍 Is a key protective gene damaged?
TP53 mutations are linked to more aggressive bladder cancers. This gives your doctor important information about how your cancer may behave over time.
Watch & Learn
Common Questions
Bladder Cancer Biomarkers — Your Questions Answered
Who should get FGFR3 testing?
All patients with locally advanced or metastatic bladder cancer should have FGFR3 testing. It’s done on your tumor tissue and can open the door to a specific targeted drug if positive.
What if my cancer is FGFR3-negative?
Most bladder cancers are FGFR3-negative. Platinum-based chemotherapy is the main first-line treatment, often followed by immunotherapy maintenance with avelumab.
How does immunotherapy work in bladder cancer?
Immunotherapy blocks a signal cancer uses to hide from your immune system. When that signal is blocked, your immune cells can find and attack the cancer. It works best in patients with higher PD-L1 levels.
Should I ask about comprehensive genomic profiling?
Yes — especially if standard treatments haven’t worked. Broader testing can find other actionable mutations like HER2 amplification that standard panels may miss.
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