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Multiple Myeloma(MM) is genetically complex and heterogeneous neoplasm in which cytogenetics is major genetic factor which plays an important role in the risk stratification of disease. High risk MM based upon cytogenetic classification includes primary IGH translocations t(4;14), t(14;16), t(14;20), and secondary progressive aberrations such as gain/Amp(1q) , 1p deletion , del(17p) & hypodiploidy. Several studies have proved that interphase FISH can efficiently detect primary as well as secondary cryptic aberrations very efficiently in lowest 5%- 10% abnormal plasma cells population. Present large scale study was undertaken to evaluate the incidence of cytogenetic abnormalities , to analyse the correlation of conventional karyotyping with FISH and to seek the geographic heterogeinity in the incidence of primary as well as secondary aberrations in our Indian vs Western population. We conducted prospective studies of 1104 patients consecutively referred from the primary, secondary and tertiary oncology centres from all over India. Interphase FISH was performed on isolated plasma cells. karyotype analysis was done as per ISCN, 2016,2020. In present large scale studies from India, FISH could detect cytogenetic abnormalities in 67.6% cases with an incidence of 59% non-hyperdiploidy(NHD). The incidence of IGH translocation was 26% vs literature frequency of 40%-50% which was mainly affected by low incidence 6% of t(11;14) in contrast to 15-20% in other series. Additionally, the association of secondary progressive aberrations in hyperdiploid (HD)group than non-hyperdiploid group in our patients is not a common finding . A biallelic inactivation of TP53 as an ultra-high risk factor was detected in old-aged patients. These observations disclose the novel findings and strongly indicate the racial disparity which leads to geographic heterogeneity. In contrast to FISH, conventional karyotyping could detect MM-related aberrations in 50% cases , of which 44% revealed highly complex karyotype with common aberrations of chromosome 1q. Overall FISH was found to be novel , easy approach with high success rate and capability of detection of all cytogenetic abnormalities that add valid information for the risk stratification of disease which in future in combination with mutation profile and Gene expression profile will help in further refinement of disease & identification of actionable targets.

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