INVESTIGATION OF CYTOGENETIC ABNORMALITIES IN NEWLY DIAGNOSED MULTIPLE MYELOMA PATIENTS BY OPTICAL GENOME MAPPING

Objective: Multiple myeloma (MM) is a neoplasm characterised by malignant proliferation of plasma cells. The FISH study on plasma cells is the main tool for cytogenetic analysis. Optical genome mapping (OGM) uses a combination of cytogenetic, FISH, and chromosomal microarray techniques to detect abnormalities with greater sensitivity. In this study, we aimed to illuminate the lesser-known cytogenetic aspects of MM using OGM.Materials and Methods: This study was conducted on five patients diagnosed with MM. Bone marrow samples were collected and used for flow cytometry to isolate plasma cells. OGM could not be performed in two patients. FISH was conducted on bone marrow, whereas OGM was performed on plasma cells.Results: Patient 1 had a ploidy abnormality, as revealed by FISH. Patient 2 had monosomy 13 detected by FISH; in addition, OGM revealed 10 aneuploidies, two deletions, and one duplication. No abnormalities were detected in the regions analysed by FISH in Patient 3. Along with trisomy 1q21 detected by FISH, Patient 4 had 11 copy number variations (CNVs), 10 structural variants (SVs), and seven aneuploidies detected by OGM. In Patient 5, FISH revealed trisomy 1q21, monosomy 13, and trisomy 17. OGM detected 12 aneuploidies and two CNVs.Conclusion: In MM, the use of OGM, which provides more detailed karyotypic classification, may provide valuable prognostic information for clinical practice. Newly identified abnormalities with OGM may contribute to our understanding of the aetiology and pathogenesis of the disease.