弥漫大 B 细胞性淋巴瘤中 bc1-6基因异常及其临床应用价值

A study on bc1-6 gene aberration in diffuse large B cell lymphoma and its clinical values

目的:观察中国人弥漫大 B 细胞性淋巴瘤(DLBCL)中 bcl-6基因突变、基因重排及蛋白表达的特征,探讨其存 DLBCL 发生中的作用及其临床应用价值。方法:应用聚合酶链反应(PCR)、直接测序和免疫组织化学法分析51例淋巴结内外 DLBCL 和10例淋巴结反应性增生(RLH)石蜡切片组织中 bcl-6基因5’非编码区突变高频区段E1.7、E1.8、E1.10、E1.11、E1.12的突变和蛋白表达;应用荧光原位杂交(FISH)技术检测32例淋巴结内 DLBCL 和5例 RLH 中 bcl-6基因的重排。结果:①12/51(23.5%)DLBCL 存在 bcl-6基因5’非编码区突变.主要集中于 E1.11、E1.12和 E1.10,2/10(20.0%)RLH 的生发中心细胞亦可见有 bcl-6突变;②9/32(28.1%)DLBCL 有 bcl-6基因重排,而 RLH 中均未检测到 bcl-6基因重排;③38/51 (74.5%)DLBCL 中可见 bcl-6蛋白细胞核表达,表达形式有滤泡样型、中间型、散在型,RLH 中可见生发中心细胞均呈 bcl-6阳性表达;④bcl-6基因5’非编码区突变、重排和蛋白表达之间均无显著性相关(P>0.05)。结论:①bcl-6基因突变和蛋白表达均可同时发生于 DLBCL 和 RLH 的生发中心,表明两者是生发中心和生发中心细胞起源 DLBCL 的标志,可用于诊断和鉴别诊断:②bcl-6蛋白在不同病例中的不同表达形式不仅反映了 DLBCL 的异质性,还可能与 DLBCL 的分子亚型和预后有关:③bcl-6基因重排仅发生于 DLBCL而不发生于 RLH,表明其可能参与了部分 DLBCL 的发生,并可作为 DLBCL 诊断的参考指标。

Objective To investigate the characteristics of bcl-6 mutation, rearrangement and protein expression in Chinese diffuse large B cell lymphoma （DLBCL） populations, and to explore their clinical values. Methods PCR and direct sequencing were used to identify the mutations of bcl-6 5＇-non coding regions including E1.7, E1.8, E1.10, E1.11 and E1.12, and the immunohistochenlistry was used to examine the bcl-6 expression in 51 cases of DLBCL and 10 cases of reactive lymphoid hyperplasia （RLH） paraffin-embeded tissues. The Fluoresence in situ hybridization （FISH） was performed to observe the bcl-6 gene rearrangement in 32 nodal DLBCL and 5 RLH as controls. Results ① The mutations in the E1.11, E1.12 or E1.10 of 5＇non coding region of bcl-6 were found in 12/51 （23.5%）DLBCL. The mutations were also found in the germinal center （GC） cells in two of 10 RLH but not in the mantle cells. ② 9/32（28.1%） nodal DLBCL had the bcl-6 gene rearrangement, but none of RLH did. ③ The bcl-6 expression in the nuclei was found in 38/51 （74.5%） DLBCL, showing different expression patterns including GC/FL type, intermediate type and sporadic type. The bcl-6 was expressed in the GC cells of RLH. ④ There was no statistically significant correlation among the bcl-6 mutation, the rearrangement and the protein expression（P〉0.05）. Conclusions ① The bcl-6 mutation and protein expression could occur in both DLBCL and RLH GC cells, which indicate that they might be markers for GC cells and GC cells originated DLBCL, and are useful for the diagnosis and the differential diagnosis. ② The different expression patterns of bcl-6 in the different DLBCL not only reflect the heterogeneity of DLBCL, but also might be associated with the molecular subtype and the prognosis; ③ The fact that bcl-6 gene rearrangement was only found in DLBCL but not in RLH suggests that it might at least partly participate in the pathogenesis of DLBCL, and it could be helpful for the DLBCL diagnosis.