Real-world poor prognostic impact of del(1p32) in newly diagnosed multiple myeloma among Asian populations

Abstract Background: Emerging evidence suggests that 1p32 deletion (del(1p32)) may represent an independent high-risk factor in newly diagnosed multiple myeloma (NDMM). However, its clinical significance remains underexplored in large real-world cohorts, particularly among Asian populations. Aims: To investigate the prevalence and prognostic impact of del(1p32) in Chinese patients with NDMM and assess its interaction with other high-risk cytogenetic abnormalities (HR CAs). Methods: A total of 279 NDMM patients with complete clinical and cytogenetic data who underwent FISH testing at West China Hospital from July 2022 to November 2024 were retrospectively analyzed. Patients were stratified based on del(1p32) status and further evaluated for progression-free survival (PFS) and overall survival (OS) using Kaplan–Meier and Cox regression analyses. The presence of co-occurring high-risk abnormalities and transplant status were also considered. Results: Fourteen patients (n=14, 5.0%) harbored del(1p32), with 1 case showing biallelic deletion. The patients harboring del(1p32) demonstrated a higher proportion presenting advanced R-ISS stage III disease (P=0.028) and elevated serum LDH levels (P=0.023). Consistently, they showed significantly shorter PFS (median 21.5 vs. 31.7 months, P<0.05) and OS (median 25.0 vs. 34.0 months, P<0.05) compared to those without the deletion. Notably, the patient with biallelic del(1p32) manifested extremely poor outcomes (PFS and OS both 5.77 months). In patients receiving autologous stem cell transplantation (ASCT), del(1p32) was associated with a trend toward shorter PFS (19.4 vs. 32.1 months, P=0.074). Furthermore, the presence of ≥2 additional high-risk cytogenetic abnormalities (e.g., del(17p), t(4;14), and/or 1q gain/amplification) along with del(1p32) dramatically worsened survival outcomes (mPFS and mOS both 5.77 months), indicating a synergistic adverse effect. Conclusions: Del(1p32) is a rare but adverse prognostic marker in NDMM and retains its predictive value even in the context of ASCT. These findings highlight the need to include del(1p32) in future risk stratification models and explore tailored therapies for affected Asian patients.