Bladder Cancer Biomarkers
What Patients Need to Know
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
Why This Matters
Understanding your bladder cancer biomarker results
Until recently, most people with advanced bladder cancer had just one treatment option: chemotherapy. Biomarker testing has changed that. Knowing your tumor’s genetic makeup can open the door to targeted drugs and immunotherapy.
If you have muscle-invasive or metastatic bladder cancer, ask your doctor: ‘Has my tumor been tested for FGFR3 mutations and PD-L1?’
The Biomarkers Your Doctor Tests
🔍 Does your cancer have a gene change that can be targeted?
FGFR3 mutations are found in about 15–20% of advanced bladder cancers. If you have one, erdafitinib (Balversa) — the first targeted drug approved specifically for bladder cancer — may be an option for you.
🔍 Will immunotherapy help your immune system fight the cancer?
PD-L1 is tested to see if your immune system can be activated against the cancer. Immunotherapy drugs like pembrolizumab or atezolizumab may be used in bladder cancer based on PD-L1 results.
🔍 Is a key protective gene damaged?
TP53 mutations are linked to more aggressive bladder cancers. This information helps your doctor understand how the cancer is likely to behave over time.
Common Questions
Bladder Cancer Biomarkers — Frequently Asked Questions
❓ Who should get FGFR3 testing?
All patients with locally advanced or metastatic urothelial carcinoma (bladder cancer) should have FGFR3 testing. It’s a simple test done on your tumor tissue and can open the door to a specific targeted drug.
❓ What if my cancer is FGFR3-negative?
Most bladder cancers are FGFR3-negative. For these patients, standard chemotherapy (usually platinum-based) is the main first-line treatment, often followed by immunotherapy maintenance with avelumab.
❓ How does immunotherapy work in bladder cancer?
Immunotherapy drugs block a signal that cancer uses to hide from your immune system. When that signal is blocked, your immune cells can recognize and attack the cancer. It works best in patients with higher PD-L1 expression.
❓ Is there genetic testing for bladder cancer beyond FGFR3?
Yes. Comprehensive genomic profiling can find other actionable alterations, including HER2 amplification and ERBB2 mutations. Ask about broader testing, especially if standard treatments haven’t worked.
Know Your Biomarkers. Own Your Journey.
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Visit the Bladder Cancer Center → Full Biomarkers Guide →
