A20基因缺失对弥漫大B细胞淋巴瘤临床病理特征和预后的影响及相关分子机制研究

目的 检测弥漫大B细胞淋巴瘤(DLBCL)中肿瘤坏死因子α诱导蛋白3基因(A20基因)缺失情况,探讨A20基因缺失对DLBCL临床过程及预后的影响及其与核因子-κB(NF-κB)通路活化的关系.方法 荧光原位杂交检测其A20基因缺失情况;免疫组织化学染色检测肿瘤中A20、Survivin、P65、Ki-67蛋白的表达,TUNEL技术检测肿瘤细胞凋亡水平,收集临床病理资料并随访,进行统计分析.结果 DLBCL病例A20基因缺失率为21.7％,活化后B细胞样型(ABC)-DLBCL的A20基因缺失率明显高于生发中心B细胞样型(GCB)-DLBCL(30.6％ vs.8.3％,P＜0.05),A20蛋白表达与A20基因缺失呈负相关(r=-0.259,P=0.023),P65蛋白和Survivin蛋白表达与A20基因缺失呈正相关(r=0.280、0.313,P=0.015、0.007);肿瘤细胞凋亡在A20基因缺失的DLBCL病例中较低,在A20蛋白表达阳性病例中明显高于表达阴性病例,在Survivin和P65蛋白阳性表达病例中明显低于阴性表达病例(P＜0.05),而在ABC-DLBCL和GCB-DLBCL病例间差异无统计学意义(P＞0.05);COX回归分析结果显示,年龄、A20基因的缺失、DLBCL类型和Ki67表达是DLBCL独立的生存相关因素;A20基因缺失者的生存状况明显较未缺失者差(P=0.015).结论 A20缺失可能影响A20蛋白表达,使其对NF-κB活化的负调节作用减弱,使Survivin表达上调而影响肿瘤细胞的增殖和凋亡;A20基因缺失对DLBCL的临床过程和预后有一定影响.

Impacts of A20 gene deletion on clinicopathological features and prognosis of diffuse large B cell lymphoma and relative molecular mechanism

Objective To detect the A20 gene deletion,investigate the impacts of A20 gene deletion on clinicopathological features and prognosis of DLBCL,and relationship between activation of NF-κB pathway and relative molecular pathogenesis.Methods A20 gene deletion was detected by fluorescence in situ hybridization (FISH).The expression of A20,Survivin,P65 and Ki-67 were detected by immunohistochemistry stain.Apoptosis was assayed by TUNEL.Follow-up and statistical analysis were done.Results The deletion rate of A20 gene was 21.7％.The deletion rate of A20 gene was obviously higher in ABC-like DLBCL than that in GCB-like DLBCL (30.6％ vs.8.3％,P＜0.05).It was observed that there was a negative correlation between A20 protein expression and A20 gene deletion (r=-0.259,P =0.023).The expression of P65 and Survivin protein was positively correlated with the A20 gene deletion (r=0.280,P =0.015;r =0.313,P =0.007).Apoptosis rate was significantly reduced in DLBCL patients with A20 gene deletion.The apoptosis rate was higher in cases with positive expression of A20 protein,while that was lower in cases with positive expression of p65 and Survivin protein than those with negative expression of corresponding protein.There was no statistically significant difference in apoptosis rate between ABC-like and GCB-like DLBCL patients (P＞0.05).COX regression analysis indicated that age,A20 gene deletion,types of DLBCL and Ki67 expression were independent factors associated with survival status.Log-rank test showed that there was a statistical difference in survival status between the cases with and without A20 gene deletion (P=0.015).Conclusion A20 gene deletion may associate with the attenuation of A20 protein expression.The latter weakens negative feedback regulation of A20 protein for NF-κB pathway.An up-regulated expression of Survivin and abnormal proliferation and apoptosis may be result from the abnormal activation of NF-κB.A20 gene deletion brings certain influence on clinical course and prognosis of DLBCL.