Cytogenetic Abnormalities in Multiple Myeloma Patients Detected by Fluorescence In Situ Hybridisation at the Lagos University Teaching Hospital

This study characterises cytogenetic abnormalities in multiple myeloma (MM) patients at the Lagos University Teaching Hospital using fluorescence in situ hybridisation (FISH), addressing a critical diagnostic gap in risk-stratified myeloma management in Nigeria. Cytogenetic classification of multiple myeloma is essential for prognosis and treatment selection, yet FISH-based myeloma cytogenetics is virtually absent from Nigerian haematology practice. A cross-sectional analytical study recruited 60 newly diagnosed MM patients confirmed by bone marrow trephine biopsy and serum electrophoresis. FISH was performed on plasma cell-enriched bone marrow preparations using probes for del(17p), t(4;14), t(14;16), t(11;14), gain(1q21), and del(13q14). Thirty-five of 60 patients (58.3%) harboured at least one high-risk cytogenetic abnormality. Del(13q14) was the most frequent abnormality (41.7%), followed by gain(1q21) (33.3%), t(4;14) (21.7%), del(17p) (16.7%), and t(14;16) (10.0%). High-risk cytogenetics (del17p, t(4;14), or t(14;16)) were present in 38.3 percent, associated with significantly shorter progression-free survival at 12-month follow-up. Gain(1q21) co-occurred with del(13q) in 62 percent of positive cases. These findings establish the first FISH-based cytogenetic landscape for Nigerian multiple myeloma and demonstrate a higher frequency of high-risk abnormalities than many European cohorts. The study advocates for routine FISH cytogenetic testing at myeloma diagnosis in all Nigerian centres capable of performing the assay. Keywords: multiple myeloma, FISH, cytogenetics, risk stratification, Lagos.