Validation of interphase fluorescence in situ hybridization (iFISH) for multiple myeloma using CD138 positive cells

Abstract

BackgroundMultiple myeloma is a plasma cell neoplasm with acquired genetic abnormalities of clinical and prognostic importance. Multiple myeloma differs from other hematologic malignancies due to a high fraction of low proliferating malignant plasma cells and the paucity of plasma cells in bone marrow aspiration samples, making cytogenetic analysis a challenge. An abnormal karyotype is found in only one-third of patients with multiple myeloma and interphase fluorescence in situ hybridization is the most useful test for studying the chromosomal abnormalities present in almost 90% of cases. However, it is necessary to study the genetic abnormalities in plasma cells after their identification or selection by morphology, immunophenotyping or sorting. Other challenges are the selection of the most informative FISH panel and determining cut-off levels for FISH probes. This study reports the validation of interphase fluorescence in situ hybridization using CD138 positive cells, according to proposed guidelines published by the European Myeloma Network (EMN) in 2012.MethodBone marrow samples from patients with multiple myeloma were used to standardize a panel of five probes [1q amplification, 13q14 deletion, 17p deletion, t(4;14), and t(14;16)] in CD138+ cells purified by magnetic cell sorting.ResultsThis test was validated with a low turnaround time and good reproducibility. Five of six samples showed genetic abnormalities. Monosomy/deletion 13 plus t(4;14) were found in two cases.ConclusionThis technique together with magnetic cell sorting is effective and can be used in the routine laboratory practice. In addition, magnetic cell sorting provides a pure plasma cell population that allows other molecular and genomic studies.

Concepts of Double Hit and Triple Hit Disease in Multiple Myeloma, Entity and Prognostic Significance

“…One of the major disadvantages of FISH method is the dependency to the quantity of bone marrow plasma cell percentage. Interphase FISH method with plasma cell enrichment by CD 138 labelling rather than examining on cultured bone marrow samples are suggested for higher detection rates of genetic abnormalities 8,9 . To date, European Myeloma Network recommends Interphase FISH method for MM and states as acceptable, till plasma cell enrichment methods becomes more accessable and less costly 10 .…”

Double hit/triple hit multiple myeloma: Myeloma with worse prognosis

“…At the time of diagnosis, it is recommended to determine specific cytogenetic abnormalities using FISH method. [5][6][7][8] Due to the slow proliferation capacity of plasma cells in MM, FISH method rather than the metaphase cytogenetic method is regarded to be plausible for the detection of translocations in clonal cells. One of the major disadvantages of FISH method is the dependency to the quantity of bone marrow plasma cell percentage.…”

Near tetrapoloid karyotype with translocation t(11;14) in a Moroccan patient with amyloid light-chain amyloidosis and multiple myeloma

“…R-banding was performed by standard techniques. Karyotype was described according to the International System for Human Cytogenetic Nomenclature ISCN (2016) [11] .…”