中文摘要：

目的：探讨micorRNA-335（miR-335）表达及甲基化水平在多发性骨髓瘤（MM）诊断中的应用。 方法：用荧光定量PCR检测43例MM患者和30例体检健康者外周血单个核细胞（PBMC）中miR-335的表达水平，用甲基化特异性PCR（MSP）检测miR-335启动子区甲基化水平，分析其与各临床指标的相关性。 结果：43例MM患者PBMC中miR-335的表达水平为34.8（15.3，84.9），显著低于健康对照组的269.4（63.3，780.2），Z=4.384，P〈0.05。11例MM患者（25.6%，11/43）呈现完全甲基化，其余患者均为部分甲基化，而23例体检健康者（76.7%）呈现完全非甲基化（Uc=6.62，P〈0.05）。初诊MM患者miR-335表达量高于复发/进展期患者（Z=2.309，P〈0.05），但复发/进展期患者中miR-335启动子区甲基化程度（75%）高于初诊患者（25%），T=24.5，P〈0.05。MM患者miR-335表达水平与轻链λ浓度呈相关性（r=0.51，P〈0.05）。 结论：MM患者miR-335表达水平和甲基化可作为MM潜在的辅助诊断指标。

英文摘要：

Objective：To investigate the role of the expression and methylation of micorRNA-335 （miR-335） in the diagnosis of multiple myeloma （MM）. Methods：The expression level and the promoter methylation status of miR-335 in the peripheral blood mononuclear cells （PBMC） from 43 MM patients and 30 healthy controls were detected by SYBR Green I QF-PCR and methylation specific PCR （MSP）, respectively, and their correlations with serum IgG, LDH, β2-M and λ chain levels were analyzed. Results：The relative expression level of miR-335 in PBMC from MM patients [34.8（15.3, 84.9）] was significantly lower than that from healthy controls[269.4（63.3, 780.2）, Z=4.384,P〈0.05]. Among 43 MM patients, there were 11 （25.6%） with miR 335 promoter completely methylated, while 23 （76.7%, 23/30） healthy controls showed completely unmethylated （Uc=6.62, P〈0.05）. The relative expression level of miR-335 in first visit patients was significantly higher than that in relapse or progressed patients （Z=2.309, P〈0.05）. However, the promoter methylation level of miR-335 in first visit patients （25%） was significantly lower than that in relapse or progressed patients （75%, T=24.5, P〈0.05）. In addition, the relative expression level of miR-335 in MM patients was correlated with λ chain concentration in serum （r=0.51, P〈0.05）. Conclusion：The expression and methylation levels of miR-335 may be helpful to the diagnosis of MM.