方法：实时定量PCR检测miR-218在视网膜母细胞瘤及瘤旁组织中的表达，并分析其与临床病理特征的关系。检测miR-218在视网膜母细胞瘤细胞系中的表达，并用miR-218模拟物转染Y79细胞，MTT及流式细胞仪检测Y79细胞的增殖、凋亡情况，RT-PCR和Western-blot法检测Bmi-1 mRNA及蛋白的表达。

结果：miR-218在视网膜母细胞瘤组织中的表达水平显著低于对应瘤旁组织； miR-218低表达与神经浸润、分化程度密切相关； miR-218可显著抑制Y79细胞的增殖并促进其凋亡，并下调Bmi-1的mRNA及蛋白表达水平。

结论：miR-218在人视网膜母细胞瘤组织中表达下调，并与临床病理相关，miR-218抑制Y79细胞增殖、促进凋亡的作用可能与下调Bmi-1有关。

METHODS:Real-time PCR was applied to detect the expression of miR-218 in human RB and the corresponding tumor-adjacent tissues to analyze the relation between miR-218 and clinic pathology characteristics. The artificial miR-218 was transiently transfected into human Y79 cells in vitro. The proliferation and apoptosis of the cells were detected by MTT assay and flow cytometry, respectively. The expression level of Bmi-1 mRNA and protein were determined by RT-PCR and Western blot.

RESULTS:The expression level of miR-218 in RB tissues was significantly lower than that in the adjacent tissues, and it was associated with optic nerve infiltration and differentiated degree. Over-expressed miR-218 in Y79 cells suppressed cell proliferation and promoted cell apoptosis, and down-regulated mRNA and protein expressions of Bmi-1.

CONCLUSION:The expression of miR-218 in RB tissues is significantly lower than that in tumor-adjacent tissues.MiR-218 could inhibit RB cell proliferation and induce apoptosis by down-regulating the expression of Bmi-1.