Observation on frequency & clinico-pathological significance of various cytogenetic risk groups in multiple myeloma: an experience from India
Pratibha S Kadam Amare1, Hemani Jain1, Shraddha Nikalje1, Manju Sengar2, Hari Menon2, Nitin Inamdar3, PG Subramanian4, Sumeet Gujral5, Tanuja Shet5, Sridhar Epari5, Reena Nair2
1 Department of Cancer Cytogenetics, Tata Memorial Hospital, Mumbai, India
2 Department of Medical Oncology, Tata Memorial Hospital, Mumbai, India
3 Department of Biochemistry, Tata Memorial Hospital, Mumbai, India
4 Department of Hematopathology, Tata Memorial Hospital, Mumbai, India
5 Department of Pathology, Tata Memorial Hospital, Mumbai, India
Pratibha S Kadam Amare
Department of Cancer Cytogenetics, Tata Memorial Hospital, 7th Floor, Annex Bldg, Dr. Ernest Borges Road, Parel, Mumbai 400 012, Maharashtra
Source of Support: None, Conflict of Interest: None
Background & objectives: Multiple myeloma (MM) is a plasma cell malignancy characterized by cytogenetic heterogeneity. In comparison with conventional karyotyping, fluorescence in situ hybridization (FISH) can efficiently detect various genetic changes in non-cycling plasma cells in 50-90 per cent of MM cases. The present study was undertaken in MM patients to evaluate the frequency and clinico-pathological significance of various cytogenetic abnormalities in the Indian population.
Methods: Interphase FISH was applied on purified plasma cells of 475 patients with MM using specific probes. Interphase FISH for 1q gain/1q amplification was performed on a separate group of 250 newly diagnosed MM patients.
Results: Low frequency of Δ13 [-13/del(13q)] (32%) and t(11;14) (5%) was observed in our 475 patients probably due to ethnic diversity. Clustering of Δ13, del(17)(p13.1) and IgH translocations in non-hyperdiploidy confirmed prognostic significance of ploidy in MM. t(4;14) and del(17)(p13.1) were high-risk groups due to correlation with high serum β2-microglobulin, increased plasma cells and advanced disease. Hyperdiploidy and t(14;16) were associated with higher age group. In a separate group of 250 patients, 1q amplification [amp(1q)] in combination with Δ13 and/or del(17p) with t(4;14) revealed association with adverse clinico-laboratory features, which confirmed progressive role of amp(1q) with adverse prognostic impact. Amp(1q) was clustered at 1q21 and 1q25 loci.
Interpretation & conclusions: Based on our findings, it appears that comprehensive analysis of various cytogenetic aberrations by interphase FISH is a powerful strategy being adapted for risk stratification of MM.