Monoclonal gammopathy: Is it cancer?

Is monoclonal gammopathy related to cancer? Does it ever cause symptoms?

- Gustav / Pennsylvania

Mayo Clinic hematologist Ruben Mesa, M.D., and colleagues answer select questions from readers.

Answer

Monoclonal gammopathy of undetermined significance (MGUS) is a noncancerous condition. However, it may increase the risk of certain cancers, including multiple myeloma.

The finding of monoclonal gammopathy on a blood test means that an abnormal protein (M protein) has been detected in your blood. Monoclonal gammopathy is present in 2 percent to 4 percent of adults older than age 50. The condition is often found on a routine blood test — called plasma electrophoresis — done for some other reason.

Monoclonal gammopathy typically causes no signs or symptoms and doesn't require treatment. In most cases, monoclonal gammopathy is not related to a serious disorder. However, close follow-up is often recommended for people with monoclonal gammopathy due to their increased risk of cancer. About 1 percent of individuals with monoclonal gammopathy ultimately develop multiple myeloma or a related cancer.

If you have a family history of multiple myeloma, talk to your doctor about whether testing for monoclonal gammopathy is appropriate for you.