Soluble BCMA (sBCMA) levels are elevated in monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM). However, the association between sBCMA levels and prognosis in MGUS and SMM has not been studied. We retrospectively analyzed sBCMA levels in stored samples from 99 MGUS and 184 SMM patients. Baseline sBCMA levels were significantly higher in MGUS and SMM patients progressing to MM during clinical follow up. When stratified according to the median baseline sBCMA level for each cohort, higher levels were associated with a shorter PFS for MGUS (HR 3.44 comparing sBCMA ≥77 vs <77 ng/mL [95% CI 2.07–5.73, p < 0.001] and SMM (HR 2.0 comparing sBCMA ≥128 vs <128 ng/mL, 95% 1.45–2.76, p < 0.001) patients. The effect of sBCMA on PFS was similar even after adjusting for the baseline MGUS or SMM risk stratification. We evaluated paired serum samples and found that sBCMA increased significantly in MGUS and SMM patients who eventually progressed to MM, whereas among MGUS non-progressors the sBCMA level remained stable. While our results require independent validation, they suggest that sBCMA may be a useful biomarker to identify MGUS and SMM patients at increased risk of progression to MM independent of the established risk models.

可溶性 BCMA (sBCMA) 水平在意义不明的单克隆丙种球蛋白病 (MGUS) 和冒烟型多发性骨髓瘤 (SMM) 中升高。然而，尚未研究 sBCMA 水平与 MGUS 和 SMM 预后之间的关联。我们回顾性分析了 99 名 MGUS 和 184 名 SMM 患者的存储样本中的 sBCMA 水平。在临床随访期间进展为 MM 的 MGUS 和 SMM 患者的基线 sBCMA 水平显着升高。当根据每个队列的中位基线 sBCMA 水平进行分层时，MGUS 的较高水平与较短的 PFS 相关（HR 3.44 比较 sBCMA ≥77 vs <77 ng/mL [95% CI 2.07–5.73, p  < 0.001] 和 SMM （HR 2.0 比较 sBCMA ≥128 与 <128 ng/mL，95% 1.45–2.76，p < 0.001) 患者。即使在调整基线 MGUS 或 SMM 风险分层后，sBCMA 对 PFS 的影响也相似。我们评估了配对血清样本，发现最终进展为 MM 的 MGUS 和 SMM 患者的 sBCMA 显着增加，而在 MGUS 非进展者中，sBCMA 水平保持稳定。虽然我们的结果需要独立验证，但他们表明 sBCMA 可能是一种有用的生物标志物，可独立于已建立的风险模型识别 MGUS 和 SMM 患者进展为 MM 的风险增加。