Incidence of cytogenetic abnormalities detected by FISH analysis in multiple myeloma: a seven-year study in King Chulalongkorn Memorial Hospital, Thailand (2018–2024)

Abstract

Background: Multiple myeloma (MM) is a genetically heterogeneous plasma cell malignancy with cytogenetic abnormalities that influence the prognosis and treatment outcomes. Fluorescence in situ hybridization (FISH) is crucial for detecting clinically significant abnormalities, including immunoglobulin heavy chain locus (IGH) translocations and deletions, e.g., del(17p), particularly in non-dividing plasma cells. However, cost and accessibility challenges limit comprehensive testing in resource-constrained settings, such as in Thailand.

Objective: This study aimed to investigate the incidence of cytogenetic abnormalities detected by FISH in MM cases over seven years in a Thai population, thereby highlighting regional trends and barriers to comprehensive testing.

Methods: A retrospective analysis was performed on 360 bone marrow samples from patients with MM between 2018 and 2024. FISH analysis targeted key abnormalities using specific probes: t(4;14), t(11;14), t(14;16), del(17p), and 1q21 amplification. Furthermore, the demographic data and testing frequencies were analyzed, as well as the prevalence rates of abnormalities were reported.

Results: Among the 360 cases, 47.4% exhibited abnormalities. The most common were del(17p) (30.6%), del(13q) (16.9%), and t(4;14) (6.9%). Testing limitations led to selective probe usage, with del (17p) probes ordered in 96.7% of cases, while 1q21 amplification probes were only ordered in 3.3% of cases. Regional trends revealed lower frequencies of t(11;14) compared to Western cohorts, suggesting ethnic influences.

Conclusion: FISH analysis revealed critical cytogenetic abnormalities in Thai patients with MM. However, financial constraints limit comprehensive testing, thus potentially hindering optimal risk stratification and treatment. Expanding diagnostic accessibility and integrating advanced technologies such as next-generation sequencing could address these barriers and improve patient outcomes.