Modified cIg-FISH protocol for multiple myeloma in routine cytogenetic laboratory practice

Area of Science:

• Cytogenetics
• Hematology
• Molecular Diagnostics

Background:

• International Myeloma Working Group recommends fluorescence in situ hybridization (FISH) on specifically identified plasma cells (PC) for multiple myeloma (MM).
• Traditional karyotyping and conventional FISH lack specificity and sensitivity for PC due to low proliferation rates and inability to distinguish cell types.
• Current PC selection methods (flow cytometry, immunomagnetic sorting, cytoplasmic labeling) are complex, time-consuming, and not routine in cytogenetic labs.

Purpose of the Study:

• To develop and validate a modified, easily integrated FISH technique for specific plasma cell analysis in multiple myeloma.
• To improve the accuracy and efficiency of detecting chromosomal abnormalities in multiple myeloma plasma cells.

Main Methods:

• A modified technique using fixed cell pellets with immunostaining and subsequent FISH (cytoplasmic immunoglobulin FISH, cIg-FISH) was developed.
• Twenty multiple myeloma patient samples were analyzed using routine FISH, cIg-FISH, and chromosomal karyotyping.
• Validation involved three FISH probes targeting t(4;14), t(14;16), and TP53 deletion.

Main Results:

• The modified cIg-FISH technique successfully identified and separated plasma cells for analysis.
• Results from cIg-FISH were comparable to established methods, demonstrating its efficacy.
• The technique proved easily incorporable into standard cytogenetic laboratory workflows.

Conclusions:

• The developed cIg-FISH technique provides a practical and accurate method for analyzing chromosomal abnormalities in multiple myeloma plasma cells.
• This technique overcomes the limitations of conventional methods, offering enhanced specificity and ease of use for routine diagnostics.
• cIg-FISH represents a valuable advancement for the cytogenetic diagnosis and management of multiple myeloma.