Biomarker Resource Center
Multiple Myeloma Biomarkers
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 signal your cancer leaves behind. Doctors find these signals in your blood or tumor tissue. The signals tell your doctor important things — like what type of cancer you have and how it is behaving.
Think of it like a clue. Your doctor collects clues from your biomarker test results. Those clues help build a picture of your cancer. That picture helps your doctor and you have a more informed conversation about next steps.
Everyone’s cancer is different — even people with the same type of cancer can have very different results. That is why biomarker testing matters. It helps your care team understand your cancer specifically.
For Multiple Myeloma
Why do biomarkers matter in multiple myeloma?
Multiple myeloma is tracked mainly through blood and urine tests. The most important marker is called M protein — an abnormal protein made by myeloma cells. Tracking M protein over time is one of the main ways your doctor monitors how your myeloma is responding. Ask your doctor to explain your key marker levels.
💬 A good question to ask your doctor: Ask your doctor what your M protein level is and how it will be tracked over time. This is your main monitoring tool throughout myeloma care.
The most important multiple myeloma biomarkers are M protein, free light chains, and beta-2 microglobulin. Together they give your doctor a clear picture of disease activity and how well treatment is working over time.
Patient Poll
Have you had biomarker testing for your multiple myeloma?
The Tests Your Doctor May Order
🔍 Is there an abnormal protein in your blood or urine?
M protein is made by myeloma cells. It is measured with blood and urine tests. Your doctor tracks M protein levels over time to monitor how your myeloma is responding. Ask your doctor what your current M protein level is and what changes to watch for.
🔍 Are protein fragments from myeloma cells in your blood?
Free light chains are pieces of M protein that can be measured in your blood. Your doctor uses the ratio and levels of these chains to help monitor your myeloma. Ask your doctor what your free light chain results mean.
🔍 Does this level tell your doctor about disease burden?
Beta-2 microglobulin is a protein that gives your doctor information about the amount of myeloma present. It is used alongside other markers for staging. Ask your doctor what your beta-2 microglobulin level means.
Watch & Learn
Important: This page is for education only. It is not medical advice. Every patient’s situation is different. Please talk to your doctor or care team about what your biomarker results mean for you specifically.
Common Questions
Multiple Myeloma Biomarkers — Your Questions Answered
How is M protein measured?
M protein is measured through a blood test called SPEP and a urine test called UPEP. Your doctor will explain what your levels mean and how often they will be checked.
What does it mean if M protein goes down?
A falling M protein level is generally a sign that your myeloma is responding. Ask your doctor what changes in your M protein level mean and what you should watch for.
What is MRD testing?
MRD stands for minimal residual disease. It is a very sensitive type of testing that looks for myeloma even when standard tests show nothing. Ask your doctor whether MRD testing is relevant for your situation.
Is there a patient support community for myeloma?
Yes. The Multiple Myeloma Research Foundation at themmrf.org and the International Myeloma Foundation at myeloma.org are trusted resources for patients and families.
Quick Links
From the Multiple Myeloma Cancer Center on XpertPatient
Have questions about your diagnosis?
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Visit the Multiple Myeloma Center → Full Biomarkers Guide →
