Soluble B-cell maturation antigen (sBCMA) is overexpressed on multiple myeloma (MM) cells. We investigated whether sBCMA levels correlated with other myeloma tumor volume indicators and its utility in monitoring oligo-secretory/non-secretory (O-S/Non-S) MM. In 115 patients with newly diagnosed MM, sBCMA was compared with M-protein levels, bone marrow plasma cells (BMPCs), circulating tumor cells (CTCs), and total diffusion volume (tDV; estimated by whole-body diffusion-weighted magnetic resonance imaging) at diagnosis. sBCMA levels increased significantly with International Staging System stage, chromosome 1q21 gain/amplification and CTC levels. sBCMA also correlated strongly with %BMPC (r = 0.65), moderately with tDV (r = 0.55) and paraprotein levels (involved immunoglobulin in IgG and IgA subtypes, r = 0.44 and 0.4; involved free light-chain levels in light-chain-only MM, r = 0.61, all P < 0.05). Longitudinal changes in sBCMA were consistent with disease status in both 17 O-S/Non-S and other secretory MM cases. Furthermore, sBCMA levels increased as early as 6 months pre-relapse in almost all O-S/Non-S relapsed patients. Thus, sBCMA correlates strongly with total tumor volume in MM, as assessed using different modalities. We suggest that sBCMA is useful, not only for monitoring responses in patients with O-S/Non-S MM but also for early relapse detection and prediction.

中文翻译：

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可溶性 B 细胞成熟抗原水平用于寡分泌和非分泌复发性多发性骨髓瘤的疾病监测。


可溶性 B 细胞成熟抗原 （sBCMA） 在多发性骨髓瘤 （MM） 细胞上过表达。我们研究了 sBCMA 水平是否与其他骨髓瘤肿瘤体积指标相关，及其在监测寡分泌/非分泌 （O-S/Non-S） MM 中的效用。在 115 例新诊断的 MM 患者中，将 sBCMA 与诊断时的 M 蛋白水平、骨髓浆细胞 （BMPCs）、循环肿瘤细胞 （CTC） 和总弥散体积 （tDV;sBCMA 水平随着国际分期系统分期、染色体 1q21 增益/扩增和 CTC 水平的增加而显著增加。sBCMA 还与 %BMPC （r = 0.65） 密切相关，与 tDV （r = 0.55） 和副蛋白水平 （IgG 和 IgA 亚型中涉及免疫球蛋白，r = 0.44 和 0.4;仅轻链 MM 中涉及游离轻链水平，r = 0.61，均 P < 0.05）。sBCMA 的纵向变化与 17 例 O-S/Non-S 和其他分泌型 MM 病例的疾病状态一致。此外，几乎所有 O-S/Non-S 复发患者的 sBCMA 水平早在复发前 6 个月就升高。因此，sBCMA 与 MM 中的总肿瘤体积密切相关，如使用不同方式评估的那样。我们认为 sBCMA 不仅可用于监测 O-S/Non-S MM 患者的反应，还可用于早期复发检测和预测。