Multiplex ligation‐dependent probe amplification and fluorescence in situ hybridization are complementary techniques to detect cytogenetic abnormalities in multiple myeloma

Multiple myeloma (MM) is a genetically heterogeneous disease with diverse clinical outcomes. Interphase fluorescence in situ hybridization (i‐FISH) is the most commonly used approach to detect recurrent cytogenetic abnormalities in this malignancy. We aimed to assess the performance of multiplex ligation‐dependent probe amplification (MLPA) to reveal copy number abnormalities (CNAs) in MM. Diagnostic bone marrow samples from 81 patients were analyzed using 42 MLPA probes for the following regions: 1p32‐31, 1p21, 1q21.3, 1q23.3, 5q31.3, 12p13.31, 13q14, 16q12, 16q23, and 17p13. All samples were also screened by i‐FISH for the presence of hyperdiploidy, deletion/monosomy of chromosome 13, deletion of TP53, disruption of the immunoglobulin heavy‐chain gene, t(4;14), t(11;14), t(14;16), t(8;14), gain of 5q and abnormalities of chromosome 1. A total of 245 alterations were detected in 79 cases (98%). Investigating the same aberrations, the two methods showed a congruency of higher than 90%. A low proportion of cells with the relevant abnormality, focal CNAs and unmatched probes were responsible for the discrepancies. MLPA revealed 95 CNAs not detected by i‐FISH providing additional information in 53 cases (65%). Scrutiny of CNAs on chromosome 1, using more than 20 probes, revealed significant heterogeneity in size and location, and variable intra‐chromosomal and intra‐clonal rates of loss or gain. Our results suggest that MLPA is a reliable high‐throughput technique to detect CNAs in MM. Since balanced aberrations are key to prognostic classification of this disease, MLPA and i‐FISH should be applied as complementary techniques in diagnostic pathology. © 2013 Wiley Periodicals, Inc.