Multiple Myeloma

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Diseases that Precede Multiple Myeloma: MGUS

Dr. Irene Ghobrial Dana-Farber Cancer Institute

Multiple myeloma can begin with conditions people have long before they ever have cancer. These conditions in the early phase are called precursor conditions.

One of them is called MGUS, or monoclonal gammopathy of undetermined significance. But having MGUS doesn’t mean you get cancer. “Over the age of 50, three percent of the population walking around have MGUS, but they don’t know about it,” says Dr. Irene Ghobrial, medical oncologist and multiple myeloma expert at Dana Farber Cancer Institute.

Although the current treatment for patients with MGUS is “watchful waiting,” researchers are currently working to find markers associated with patients’ MGUS that could indicate that they are at a high risk of progressing to active myeloma.

“The hope in the future is that we can define what is the best therapy for that individual patient, and then we give it to them,” Dr. Ghobrial says.

Understanding MGUS

MGUS is a precancerous condition in which an abnormal protein turns up in the blood. The protein, produced by a type of white blood cell in the bone marrow called plasma cells, usually causes no health problems, and people are typically unaware they have MGUS until it is diagnosed in a routine blood test.

In MGUS, plasma cells make up less than 10% of the bone marrow. That’s not enough to cause cancer. Healthy people can have close to that amount. This explains why the disease is symptomless and carries only a 1% yearly risk of developing active myeloma. However, not all individuals have the same risk of developing MGUS. The risk varies by:

  • Race–African Americans are three times as likely to develop MGUS than Caucasians. The disease also typically appears at an earlier age
  • Family history–first-degree relatives of individuals with MGUS or overt active myeloma are at an increased risk of developing the same disease.
  • Age–Like many cancers and their associated conditions, risk of developing MGUS also increases with age.


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Dr. Irene Ghobrial is a Medical Oncologist at Dana-Farber Cancer Institute. Read More