MyMyelomaTeam

What is M protein in multiple myeloma?

M protein is an abnormal antibody made by cancerous plasma cells in multiple myeloma. The "M" stands for "monoclonal," though it's often called "myeloma protein."

Here's how it develops: Normal plasma cells are part of your immune system and make different antibodies to fight Show Full Answer

What is M protein in multiple myeloma?

M protein is an abnormal antibody made by cancerous plasma cells in multiple myeloma. The "M" stands for "monoclonal," though it's often called "myeloma protein."

Here's how it develops: Normal plasma cells are part of your immune system and make different antibodies to fight infections. In myeloma, one damaged plasma cell creates many identical clones of itself. These clones all produce the exact same abnormal protein—M protein.

Unlike healthy antibodies, M protein doesn't work properly. It can't fight infections effectively and may damage your kidneys and other organs.

Why does M protein matter?

M protein levels help doctors:
- Diagnose multiple myeloma and related conditions
- Determine your disease stage
- Monitor if the disease is progressing
- Track how well treatments are working

Most people with myeloma have M protein in their blood or urine. When treatment is successful, M protein levels decrease and can eventually reach zero.

Important to know: Finding M protein doesn't automatically mean you have active myeloma. It can also appear in conditions like MGUS (monoclonal gammopathy of undetermined significance) or smoldering myeloma, which have lower M protein levels and may not require immediate treatment.

Your healthcare provider will interpret your M protein levels along with other tests to understand your specific situation.

 AI-generated responses are not a substitute for medical advice. These services are not intended to diagnose, treat, or cure any condition or disease. Always ask your doctor about specific health concerns.

What Is M Protein in Multiple Myeloma?