Fluorescence in situ hybridization analysis of chromosome aberrations in 60 Chinese patients with multiple myeloma

Conventional cytogenetic analysis is often hampered owing to the low mitotic index of multiple myeloma (MM) cells in bone marrow samples of MM. Interphase fluorescence in situ hybridization (I-FISH) analysis combined with magnetic-activated cell sorting (MACS) has substantially enhanced the sensitivity of cytogenetic analysis. Here, we used I-FISH to explore the incidence of chromosomal abnormalities in 60 Chinese patients with newly diagnosed MM. Five different specific probes for the regions containing 13q14.3 (D13S319), 14q32 (IGHC/IGHV), 1q21, 1p12, and 17p13 were used to detect chromosomal aberrations, and LSI IGH/CCND1, LSI IGH/FGFR3, and LSI IGH/MAF probes were further applied to detect t(11;14)(q13;q32), t(4;14)(p16;q32), and t(14;16)(q32;q23) in patients with 14q32 rearrangement. Fifty of the patients (83.3%) had at least one type of abnormalities regarding the regions analyzed. Nine patients (15%) had one abnormality; 10 patients (16.7%) had two abnormalities; 31 patients (51.7%) had three or more abnormalities. The most frequent abnormality in the patients was illegitimate IgH rearrangement (70%), fol- lowed by 13q14 deletion (63.3%), 1q21 amplification (61.7%), 1p12 deletion (33.3%), and 17p13 deletion (13.3%). These aberrations are not randomly distributed, but strongly interconnected. Patients with 17p13 deletion or t(4;14)(p16;q32) had significant higher b2-microglobu- lin level (P 0.05). However, all these abnormalities had no correlation with age, gender, disease stage, and Ig isotype; yet, it was showed that the frequencies of the individual chromosomal abnormalities were very high. Taken together, MACS in combination with I-FISH may be a promising tool to detect the molecular cytogenetic abnormalities of MM.