Detection of genomic abnormalities in multiple myeloma: the applicationof FISH analysis in combination with various plasma cell enrichmenttechniques.

Luise Hartmann, Julie Sanford Biggerstaff, Douglas B. Chapman, Janice M. Scott, Krystal R. Johnson, Keely M. Ghirardelli, Wayne K. Fritschle, Dolores L. Martinez, Richard K. Bennington, Monica E. de Baca, Denise A. Wells, Michael R. Loken, Barbara K. Zehentner

Multiple myeloma (MM) is a hematopoietic neoplasm characterized by malignant plasma cells (PCs) that accumulate in the bone marrow. A number of different genomic abnormalities are associated with MM; however, detection of these by fluorescence in situ hybridization (FISH) can be limited by the percentage of PCs in the specimen. In this study, we tested 20 bone marrow specimens with known MM and a low concentration of monoclonal PCs for the presence of genomic abnormalities using FISH in combination with various PC enrichment techniques: magnetic cell sorting, targeted manual scoring, and automated image analysis. In addition, flow cytometric cell sorting of PCs in combination with FISH analysis was also tested for minimal residual disease applications. Different parameters were evaluated when assessing the detection efficiency of each approach. FISH results are highly dependent on the chosen enrichment method. We describe the evaluation of different techniques applicable for various laboratory settings and specimen parameters.