Prognostic significance of CD56 expression in newly diagnosed multiple myeloma and its correlation with clinicopathological features.

OBJECTIVE: To investigate the correlation of CD56 expression with clinical prognosis and adverse prognostic indicators in patients with newly diagnosed multiple myeloma (NDMM). METHODS: We conducted a retrospective cohort study of 153 NDMM patients treated at Jiaozuo People's Hospital Affiliated to Henan Medical University between May 2014 and August 2024. Patients were stratified into the bortezomib cohort and the non-bortezomib cohort based on their treatment regimens, and were further divided into CD56+ group and CD56- group according to CD56 expression status determined by flow cytometry. Prognosis and clinicopathological characteristics were compared between groups stratified by CD56 expression and treatment regimen. RESULTS: No statistically significant differences in median progression-free survival (PFS) or overall survival (OS) were observed between the CD56+ and CD56- groups. Median PFS and OS were significantly longer in the bortezomib-based cohort than in the non-bortezomib cohort, whereas no significant differences were found among patients treated with VCD, VTD, or VRD regimens. Within the bortezomib-based cohort, no significant difference in median PFS or OS was observed between CD56+ and CD56- patients. In contrast, within the non-bortezomib cohort, CD56- patients had significantly shorter median PFS and OS than CD56+ patients. Among CD56- patients, no significant differences in median PFS or OS were observed across the VCD, VTD, and VRD regimens. CD56 deficiency was associated with multiple adverse prognostic indicators, including thrombocytopenia, elevated β2-microglobulin (β2-MG), bone marrow fibrosis, advanced International Staging System (ISS) stage, complex karyotype, and cytogenetic aberrations. CONCLUSION: Bortezomib-based therapy may attenuate the adverse prognostic impact associated with CD56 deficiency. CD56 expression has prognostic significance in NDMM and is closely correlated with multiple adverse clinicopathological indicators; however, it does not serve as an independent prognostic factor for NDMM patients.