[Cytoplasmic light-chain immunofluorescence combined with FISH in bone marrow smears to detect cytogenetic abnormalities in multiple myeloma]

Objective: To analyze the sensitivity of cytoplasmic light-chain immunofluorescence with fluorescence in situ hybridization in bone marrow smears (new FISH) for detecting cytogenetic abnormalities in multiple myeloma (MM) . Methods: 42 MM patients admitted to the First Affiliated Hospital of Nanjing Medical University from April 2022 to October 2023 were enrolled. The patients with MM were detected by new FISH and CD138 immunomagnetic bead sorting technology combined with FISH (MACS-FISH) or cytoplasmic immunoglobulin FISH (cIg-FISH) to analyze cytogenetic detection results using combination probes which included 1q21/1p32, p53, IgH, IgH/FGFR3 [t (4;14) ], and IgH/MAF [t (14;16) ]. Results: In 23 patients with MM, the abnormality detection rates of cIg-FISH and new FISH were 95.7% and 100.0%, respectively (P>0.05). The detection rates of 1q21+, 1p32-, p53 deletion, and IgH abnormalities by cIg-FISH and new FISH were consistent, which were 52.2%, 8.7%, 17.4%, and 65.2%, respectively. The results of the two methods further performed with t (4;14) and t (14;16) in patients with IgH abnormalities were identical. The positive rate of t (4;14) was 26.7%, whereas t (14;16) was not detected. In 19 patients with MM, the abnormality detection rates of MACS-FISH and new FISH were 73.7% and 63.2%, respectively (P>0.05). The positivity rate of 1q21+, 1p32- and IgH abnormalities detected by MACS-FISH were slightly higher than those detected by new FISH; however, the differences were not statistically significant (all P values >0.05) . Conclusion: The new FISH method has a higher detection rate of cytogenetic abnormalities in patients with MM and has good consistency with MACS-FISH and cIg-FISH.