A practical approach to the detection of prognostically significant genomic aberrations in multiple myeloma

Multiple myeloma (MM) is a malignancy of differentiated B lymphocytes and has remained an incurable disease. Chromosomal abnormalities are among the most important prognostic parameters for MM. Cytoplasm immunoglobulin-enhanced interphase fluorescent in situ hybridization (FISH) has been a standard cell-targeting method for identifying genomic aberrations in MM. We have developed another cell-targeting approach by using CD138 magnetic microbeads to sort plasma cells for FISH analysis. The FISH panel consisted of four probes targeting RB-1, D13S319, immunoglobulin H, and p53 loci. We reviewed the FISH and conventional cytogenetic results of 60 patients with MM. The present cell-targeting approach in conjunction with the FISH probe panel was more sensitive than FISH performed on untargeted cells in detecting prognostically significant genomic aberrations (72 versus 24%, P = 0.0016). The frequencies of genomic abnormalities identified were similar to previously reported data obtained with the standard cell-targeting method. Therefore, our cell-targeting approach and FISH panel reliably detect prognostically important genomic abnormalities in MM and are potentially suitable for widespread use.