弥漫大B细胞淋巴瘤组织bcl-6蛋白表达及基因重排

目的探讨弥漫大B细胞淋巴瘤(DLBCL)中bcl-6和CD10蛋白表达以及基因重排的特点及其临床病理意义。方法应用免疫组织化学EnVision法分析51例DLBCL(22例为淋巴结内,29例为淋巴结外)和10例淋巴结反应性增生石蜡组织中bcl-6蛋白表达,并与CD10的表达作比较分析;应用断裂分离探针及间期核荧光原位杂交(FISH)技术检测32例淋巴结内DLBCL(22例为石蜡组织,10例为新鲜组织)和5例淋巴结反应性增生石蜡组织中bcl-6基因的重排。结果(1)淋巴结内、外DLBCL和淋巴结反应性增生中bcl-6蛋白均呈细胞核表达,阳性率分别为72.7%(16/22)、75.9%(22/29)、100.0%(10/10);CD10的阳性率分别为40.9%(9/22)、41.4%(12/29)、100.0%(10/10),所有CD10阳性肿瘤均共同表达bcl-6蛋白。(2)40.9%(9/22)的淋巴结内DLBCL和41.4%(12/29)的淋巴结外DLBCL为两蛋白共同阳性表达;将之与两蛋白均不表达的DLBCL(27.3%,6/22和24.1%,7/29)相比,前者(Ⅰ或Ⅱ期)的临床分期低于后者(Ⅲ或Ⅳ期,P<0.05)。(3)淋巴结内DLBCL样本中bcl6基因重排阳性率为28.1%(9/32),其中石蜡组织样本阳性率为27.3%(6/22),新鲜组织样本阳性率为30.0%(3/10),P>0.05。5例淋巴结反应性增生样本中均未检测到bcl-6基因重排,与DLBCL相比P<0.05。结论(1)在DLBCL中bcl6有较高的阳性表达率,bcl-6和CD10蛋白的联合检测可以协助DLBCL的诊断和鉴别诊断;bcl6和CD10共同阳性的DLBCL可能具有更好的预后。(2)bcl-6基因重排可能参与了部分DLBCL的发生,并可作为DLBCL诊断的参考指标。

Analysis of bcl-6 protein expression and gene rearrangement in diffuse large B-cell lymphoma

OBJECTIVE: To investigate bcl-6 protein expression and gene rearrangement patterns in diffuse large B-cell lymphoma (DLBCL) and their clinicopathologic significance. METHODS: Immunohistochemical studies for bcl-6 and CD10 proteins were performed on 51 cases of DLBCL paraffin-embedded tissues (including 22 nodal samples and 29 extranodal samples) and 10 cases of reactive lymphoid hyperplasia (RLH) paraffin-embedded tissues. Interphase fluorescence in-situ hybridization (FISH) with dual color breakapart probe was also used to identify rearrangement of bcl-6 gene in 32 cases of nodal DLBCL tissues (including 22 paraffin-embedded samples and 10 fresh samples) and 5 cases of RLH paraffin-embedded tissues. RESULTS: (1) The rates of bcl-6 protein expression in nodal DLBCL, extranodal DLBCL and RLH were 72.7% (16/22), 75.9% (22/29) and 100.0% (10/10) respectively. The rates of CD10 expression were 40.9% (9/22), 41.4% (12/29) and 100.0% (10/10) respectively. All lymphoma samples which expressed CD10 also showed co-expression of bcl-6 protein. (2) The co-expression of bcl-6 and CD10 was observed in 40.9% (9/22) nodal DLBCL and 41.4% (12/29) extranodal DLBCL. Low clinical stage (stage I and II) was more frequently observed in cases with co-expression of bcl-6 and CD10 (P < 0.05). (3) The rates of bcl-6 gene rearrangement in nodal DLBCL was 28.1% (9/32), with 27.3% (6/22) in paraffin-embedded tissues and 30.0% (3/10) in fresh tissues. There was no statistically significant difference found between the two groups (P > 0.05). Bcl-6 gene rearrangement was not found in all the 5 cases of RLH, and there was a significant difference between RLH and DLBCL (P < 0.05). CONCLUSIONS: The rate of bcl-6 protein expression is high in DLBCL cases, and the detection of bcl-6 and CD10 protein co-expression may help in the diagnosis and differential diagnosis of DLBCL. Those DLBCL cases with co-expression of bcl-6 and CD10 may also have a better prognostic implication. On the other hand, bcl-6 gene rearrangement can be identified by interphase FISH with dual color breakapart probe in both paraffin-embedded and fresh lymphoma tissues.