Cytogenetic and FISH analysis of 93 multiple myeloma Moroccan patients

Abstract

Background Multiple myeloma (MM) is a disease characterized by heterogeneous clinical presentations as well as complex genetic and molecular abnormalities. In MM, cytogenetic analysis is a challenge because of the low proliferation of malignant plasma cells. Thus, interphase fluorescence in situ hybridization (FISH), performed on sorted plasma cells detected abnormalities independently of a proliferative and infiltrative index. The purpose of this study was to explore, for the first time, the cytogenetic and molecular genetics features in Moroccan patients with multiple myeloma referred exclusively to National Reference Laboratory and to determine their risk stratification based on these features. Methods We performed cytogenetic analysis on 93 MM cases, all patients were subjected to FISH analysis, among which 45 patients have benefited from both FISH analysis and standard karyotype. Results Karyotype was normal in 78% (35/45) while, it was complex with varied structural and numerical abnormalities in 22% (10/45) of all patients, among which Hyperdiploid karyotype was found in 9% (n = 4 cases) and nonhyperdiploid in 13% (n = 6 cases). The most common numerical abnormalities were gains of chromosomes 3, 5, 9, 15, and 19. Whole chromosome losses were also frequent, affecting chromosomes X, 3, 14, 16 and 22. FISH analysis detected abnormalities in 50% of cases. The translocation t(4;14) and dup (1q) were the most frequent types of anomalies (14% and 13% respectively), followed by (17p) deletion and 14q32/IGH translocations with an undetermined origin (12% each) then the (1p) deletion (4%). For the normal karyotypes, FISH revealed chromosome abnormalities in 46%. Conclusion This study compares the results of cytogenetic analysis of chromosomal abnormalities in the Moroccan population with other countries. ½ patient showed at least one type of molecular genetic abnormalities. Therefore, the introducing of the cytogenetic analysis is obligatory in the diagnosis of multiple myeloma.

Correlations between apparent diffusion coefficient values of WB-DWI and clinical parameters in multiple myeloma

“…FISH analysis of probe hybridization was performed with a 100 × objective fluorescence microscope (Olympus BX5, Japan) with single and triple emission filters. The iFISH results were described according to the standards of the International System for Human Cytogenetic Nomenclature (ISCN) 2016 [ 9 ].…”

“…These include various cytogenetic abnormalities that influence MM risk stratification and prognosis and have become the target of new therapeutic methods. DNA probes using the interphase fluorescence in situ hybridization (iFISH) technology combined with chromosomal analysis overcomes the limitations of the conventional detection of mitotic phase chromosomes and has greatly improved the sensitivity of cytogenetic analysis [ 9 ]. High-frequency chromosomal abnormalities detected by iFISH in MM include 1q21, rearrangements at the immunoglobulin heavy chain (IGH) locus, and p53.…”

“…High-frequency chromosomal abnormalities detected by iFISH in MM include 1q21, rearrangements at the immunoglobulin heavy chain (IGH) locus, and p53. Some studies have found that these genetic mutations are significantly associated with albumin and globulin levels and affect the prognosis and treatment response of MM [9][10][11]. Mutations with high levels of albumin and globulin means that the proliferation and secretion of tumor cells are more vigorous, which indirectly means more tumor cells and smaller intercellular spaces.…”

Conventional Karyotyping and Fluorescence In Situ Hybridization for Detection of Chromosomal Abnormalities in Multiple Myeloma

“…The median age at diagnosis is 60 years old. Prognosis has been steadily improving over the last two decades alongside the introduction of new therapeutic strategies, which has prolonged the median survival from 3 to 8 - 10 years [ 1 , 2 , 3 ].…”

“…MM is diagnosed by bone marrow biopsy showing clonal bone marrow plasma cells ≥ 10% or biopsy showing plasmacytoma, and any one or more of the following myeloma-defining events: hypercalcemia, renal insufficiency, anemia, and bone lesions [ 1 , 2 ].…”