Combined Selection System to Lower the Cutoff for Plasma Cell Enrichment Applied to iFISH Analysis in Multiple...

Area of Science:

• Hematology
• Oncology
• Medical Genetics

Background:

• Multiple myeloma (MM) is a heterogeneous plasma cell malignancy.
• Cytogenetic aberrations in plasma cells (PCs) are key prognostic markers.
• Low PC infiltration in bone marrow hinders traditional cytogenetic analysis.

Purpose of the Study:

• To optimize a PC immunomagnetic isolation strategy for MM genetic analysis.
• To enable genetic studies with minimal PC infiltration (as low as 1%).
• To assess cytogenetic abnormalities in a cohort of suspected MM patients.

Main Methods:

• Analyzed 153 bone marrow samples from patients suspected of MM.
• Employed PC immunomagnetic isolation to enrich plasma cells.
• Performed immunophenotyping, conventional cytogenetics, and interphase fluorescence in situ hybridization (iFISH).

Main Results:

• The optimized method allowed genetic analysis with ≥1% PC infiltration and high purity.
• 90% of analyzed samples exhibited cytogenetic abnormalities.
• Common abnormalities included immunoglobulin rearrangements (50%), 1q gains (41.9%), 1p deletions (29.7%), and TP53 deletion (33%).

Conclusions:

• Optimized immunomagnetic isolation is effective for MM genetic analysis, even with low PC infiltration.
• The high prevalence of cytogenetic abnormalities underscores their importance in MM.
• This method facilitates accurate diagnosis and prognostic assessment in multiple myeloma.