Expression data of plasma cell from MGUS patients

Multiple myeloma is preceded by monoclonal gammopathy of undetermined significance (MGUS). Serum markers are currently used to stratify MGUS patients into clinical risk groups. A molecular signature predicting MGUS progression has not been produced. We have explored the use of gene expression profiling to risk-stratify MGUS and developed an optimized signature based on large samples with long-term follow-up. Microarray analysis of mRNA from MGUS patients with stable disease and MGUS patients that progressed to MM within 10 years, was used to define a molecular signature of MGUS risk. Bone marrow plasma cells from MGUS patients were enriched by anti-CD138 immunomagnetic beads for RNA extraction and hybridization on Affymetrix microarrays. We sought to identify genetic differences in the bone marrow plasma cells of stable and progressive MGUS patients. Patients who progressed to MM within 10 years after diagnosis of MGUS were considered Progressing (P), while the other 334 MGUS had not progressed called Stable (S).