弥漫性大B细胞性淋巴瘤中CARMA1基因突变的检测及意义

Detection of CARMA1 gene mutations and its significance in diffuse large B cell lymphoma

目的了解CARMA1基因在弥漫性大B细胞性淋巴瘤(DLBCL)中的突变情况,及其与DLBCL临床病理特征的关系。方法采用免疫组化方法检测54例DLBCL中CD10、bcl-6、mum-1和Ki-67表达情况以确定DLBCL细胞来源及增殖活性;进行石蜡组织DNA的提取。聚合酶链反应(PCR)扩增CARMA1基因外显子5、6、7、8、9,DNA直接测序检测其突变情况,并进行临床资料分析及随访。结果 54例DLBCL标本中有4例发生错义突变(7.4%),突变位点为第8外显子的110850碱基处,G突变为A。4例均为结外(胃肠)DLBCL,其中1例为GCBDLBCL(5%),3例为ABC-DLBCL(8.8%)。4例IV期3例,Ⅲ期1例,均浸润消化道全层并累及肠外脂肪组织,1例并出现淋巴结受累。LDH均升高,国际预后指数(IPI)3例为4分(高危),1例为3分(中高危);4例中3例死亡,有2例存活时间仅2年。结论在少部分DLBCL中存在CARMA1基因的错义突变,且该突变可能与DLBCL的不良预后有关。

Objective To investigate CARMA1 mutations in diffuse large B cell lymphoma （DLBCL） and its correlation with chnical pathological features of the lymphoma. Methods The expression of CD10, BCL-6, MUM-1 and Ki-67 in 54 cases of patients with DLBCL were studied by immunohistochemical method in order to determine the origin of DLBCL ceils and to understand the proliferation of neoplasm. Genomic DNA was extracted from formalin-fixed and paraffin-embedded （FFPE） tissues. Exons 5, 6, 7, 8 and 9 of CARMA1 gene were amplificated by polymerase chain reaction （PCR） and the amplified products of these exons were analyzed by direct DNA sequencing. The clinical data of patients were collected with follow-up. Results Missense mutation in exon 8 of CARMA1 gene was identified in 4 of 54 patiens （4/54, 7.4% ）. The missense mutantion was that A substituted for G at site 110850n of exon 8. 4 cases were extranodal DLBCL （gastrointestinal） DLBCL, including 1 case of GCB-DLBCL （5%, 1/20）, 3 cases of ABC-DLBCL （8.8%, 3/34）. There were later clinical stages （3 cases in stage IV, and 1 case in stage Ⅲ ）, extensive infiltration and increased LDH level. 3 cases were 4 points of the international prognostic index （IPI） and 1 case was IPI 3 points. 3 of 4 cases with the mutation of CARMA1 gene was dead, with the survival time of two years in 2 dead cases. Conclusion There is missense mutations of CARMA1 gene in a small number of diffuse large B cell lymphoma and the mutation may be associated with poor prognosis of DLBCL.