Objective: To determine the incidence and clinical significance of chromosome 13q14 deletion in multiple myeloma (MM).
Methods: Bone marrow samples were collected from 132 newly diagnosed MM patients referred to our hospital. Interphase fluorescence in situ hybridization (i-FISH) combined with magnetic activated cell sorting (MACS) were performed on chromosome 13q14 (RB-1).
Results: (1) i-FISH was used to investigate CD138-enriched bone marrow MM cells and revealed a 13q14 deletion rate of 51.5% (68/132), while conventional cytogenetic (CC) analysis revealed 13q deletions/monosomy 13 (Δ13) only of 5.0%(6/120). (2) Univariate analysis showed that 13q14 deletion rate by i-FISH > 25%, bone marrow plasma cells > 50%, ISS stage and β(2)-MG ≥ 5.5 mg/L were associated with shorter overall survival (OS). Multivariate analysis revealed that 13q14 deletion rate by i-FISH > 25% was an independent unfavorable factor (P = 0.042). (3) Patients treated with bortezomib had a much better response than those treated with traditional chemotherapy (P = 0.001). There was no significant difference in OS between patients received bortezomib with and without 13q14 deletion (P > 0.05), indicating that bortezomib could reverse the poor prognosis of 13q14 deletion.
Conclusion: (1) i-FISH followed CD138 cell sorting appears to be a highly sensitive method for detecting 13q14 deletion. (2) 13q14 deletion rate by i-FISH > 25% is an independent unfavorable factor. (3) Bortezomib could reverse the poor prognosis of 13q14 deletion.