Mayo Clinic College of Medicine and Mayo Foundation, Rochester, MN 55905, USA.
J Clin Oncol. 2011 Apr 20;29(12):1620-6. doi: 10.1200/JCO.2010.29.4413. Epub 2011 Mar 7.
The serum free light chain (FLC) assay quantitates free kappa (κ) and free lambda (λ) immunoglobulin light chains. This assay has prognostic value in plasma cell proliferative disorders. There are limited data on serum FLC in B-cell malignancies.
The association of pretreatment FLC with event-free survival (EFS) and overall survival (OS) in diffuse large B-cell lymphoma (DLBCL) was evaluated in 76 patients from the North Central Cancer Treatment Group trial N0489 (NCT00301821) and 219 patients from the University of Iowa/Mayo Clinic Specialized Program of Research Excellence Molecular Epidemiology Resource (MER). Published reference ranges were used to define an elevated FLC or an abnormal κ:λ FLC ratio.
Elevated FLC or abnormal κ:λ FLC ratio was present in 32% and 14% of patients, respectively. Patients with elevated FLC had an inferior OS and EFS in both cohorts compared with patients with normal FLC (N0489: EFS hazard ratio [HR], 3.06; OS HR, 3.16; both P < .02; MER: EFS HR, 2.42; OS HR, 3.40; both P < .001; combined EFS HR, 2.57; OS HR, 3.74; both P < .001). All associations remained significant for EFS and OS after adjusting for the International Prognostic Index (IPI). Abnormal κ:λ FLC ratio was modestly associated with outcome in the combined group (EFS HR, 1.61; OS HR, 1.67; both P = .07), but not in patients without corresponding elevated κ or λ. Elevated FLC was the strongest predictor of outcome in multivariable models with the IPI components.
Increased serum FLC is an independent, adverse prognostic factor for EFS and OS in DLBCL and warrants further evaluation as a biomarker in DLBCL.
血清游离轻链（FLC）检测定量游离κ（κ）和游离λ（λ）免疫球蛋白轻链。该检测在浆细胞增生性疾病中具有预后价值。关于 B 细胞恶性肿瘤的血清 FLC 数据有限。
评价了来自北中央癌症治疗组试验 N0489（NCT00301821）的 76 例弥漫性大 B 细胞淋巴瘤（DLBCL）患者和爱荷华大学/梅奥诊所专门研究卓越分子流行病学资源（MER）的 219 例患者的预处理 FLC 与无事件生存（EFS）和总生存（OS）的关系。使用已发表的参考范围来定义升高的 FLC 或异常的 κ：λ FLC 比值。
分别有 32%和 14%的患者存在升高的 FLC 或异常的 κ：λ FLC 比值。与 FLC 正常的患者相比，FLC 升高的患者在两个队列中的 OS 和 EFS 均较差（N0489：EFS 危险比[HR]，3.06；OS HR，3.16；均 P <.02；MER：EFS HR，2.42；OS HR，3.40；均 P <.001；合并 EFS HR，2.57；OS HR，3.74；均 P <.001）。在调整国际预后指数（IPI）后，所有关联在 EFS 和 OS 方面仍然显著。在合并组中，异常的 κ：λ FLC 比值与结局呈适度相关（EFS HR，1.61；OS HR，1.67；均 P =.07），但在没有相应升高的 κ 或 λ 的患者中没有相关性。在包含 IPI 成分的多变量模型中，升高的 FLC 是预后的最强预测因子。
血清 FLC 升高是 DLBCL 患者 EFS 和 OS 的独立不良预后因素，值得进一步作为 DLBCL 的生物标志物进行评估。
