What Are Precursor Blood Conditions and How Are They Treated?

Precursor conditions are early phases of blood diseases that may develop into cancers such as lymphoma, leukemia, Waldenström’s macroglobulinemia, and multiple myeloma. Most people do not experience symptoms, and since doctors rarely screen for precursor conditions, they are often diagnosed after routine blood tests.

Cancer research, multiple myeloma
Irene Ghobrial, MD, is working to understand why some precursor conditions develop into cancer.

“Many diagnoses are purely incidental,” says Irene Ghobrial, MD, co-principal investigator at the Center for Prevention of Progression of Blood Cancers (CPOP) at Dana-Farber Cancer Institute and medical oncologist in the Jerome Lipper Multiple Myeloma Center at Dana-Farber/Brigham and Women’s Cancer Center. Patients with a precursor condition are often told to “watch and wait.” In other words, the condition is monitored and treatment only begins if it develops into cancer. Not every person diagnosed with a precursor condition will be diagnosed with a blood cancer, but many cases of blood cancer do develop from precursor conditions.

Precursor blood conditions include:

  • Early Myelodysplastic Syndrome (MDS), a condition in which the bone marrow does not produce enough healthy blood cells. In advanced stages, MDS may progress to acute myeloid leukemia (AML).
  • Monoclonal Gammopathy of Undetermined Significance (MGUS), a condition in which there are abnormal plasma cells in the bone marrow. These cells produce monoclonal proteins, which routine blood and urine tests sometimes detect. In some cases, MGUS progresses into multiple myeloma. About 3 percent of adults over age 50 have MGUS, according to Ghobrial. Multiple myeloma is almost always preceded by MGUS, although not every case of MGUS will evolve into multiple myeloma, she explains.
  • Smoldering multiple myeloma, a condition in which there are abnormal plasma cells in the bone marrow that produce monoclonal proteins or free light-chains, smaller units of the immunoglobulin produced by plasma cells.
  • Smoldering Waldenström’s macroglobulinemia, a condition in which there are abnormal lymphocytes and plasma cells in the bone marrow that secrete monocolonal proteins of IgM type. This condition may progress to Waldenström’s macroglobulinemia.


Researchers at the CPOP, led by Robert Soiffer, MDDavid Steensma, MDBenjamin Ebert, MD, PhD; and Ghobrial, seek to understand why some patients with precursor conditions develop cancer and others do not, with the goal of some day developing treatments that can delay or stop the progression of precursor conditions, and eventually eradicate them. The research is driven by the center’s PCROWD study, which collects, processes, and stores tissue samples from people with precursor conditions from across the United States.