多发性骨髓瘤患者IgH_MMSET基因的检测及其意义_姜华

·论著·多发性骨髓瘤患者IgH-MMSET基因

的检测及其意义

姜华　侯健　陈玉宝　丁思奇

【摘要】　目的　检测多发性骨髓瘤(MM)患者由于t(4;14)所形成的IgH-MMSET融合基因,探讨其

在MM中的临床意义。方法　采用RT-PCR法在25例MM患者骨髓标本和MM细胞系NCI-H929中检

测IgH-MMSET融合基因,并且通过巢式PCR法提高反应的灵敏度。PCR产物纯化后克隆到pGE M-T载

体,并用引物M13Forward测序。将PCR产物的序列与GenBank进行对照,进一步证实发生易位的基

因。结果　作为阳性对照的MM细胞系NCI-H929扩增出一明显条带,长度为438bp,经测序后证实为

IgH基因与MMSET基因的融合产物。14号染色体及4号染色体上的断裂点分别位于IgH基因的Cμ区

及MMSET基因的第3内含子中。25例MM患者的骨髓标本扩增后有3例(12.0%)呈现阳性,经分别

测序后证实为IgH-MMSET融合基因,扩增产物的长度分别为237bp、239bp和239bp,三者第4染色体

的断裂方式均与NCI-H929相同,其中1例缺失了MMSET基因的第4外显子的第74位碱基(A)和第75

位碱基(T)。结论　MM患者IgH-MMSET融合基因是由于t(4;14)所形成,其发生率为12.0%。IgH-

MMSET融合基因的出现可能是MM患者预后不良的指标之一。

【关键词】　多发性骨髓瘤;　基因融合,IgH-MMSET;　易位(遗传学)

Detectio n of IgH-MMSET fusion gene in multiple myeloma patients and its significance　JIA NG Hua,H O U

Jian,C HEN Yu-bao,DINGSi-qi.Department of Hematology,Chang zheng Ho spital,The Second Military M edical

University,Shanghai　200003,China

【Abstract】　Objective　To detect the IgH-MMSE T fus ion gene resulted from t(4;14)translocation in mul-

tiple myeloma and illuminate its significance.Methods　IgH-MMSE T fusion gene was detected in bone marrow

specimens of25multiple myeloma(MM)patients and MM cell line NCI-H929using reverse-transcription PCR(RT-

PCR)assay followed by nested PCR to increase the sensitivity.The purified PCR products were cloned into p GE M-T

vector and then sequenced usin g M13forward primers.The fragment sequences were compared with that in GenBank

to find matched sequences.Results　Only a438base pair long fragment was obtained after RT-PCR assay and was

confirmed by sequencing to be a fusion gene product of IgH gene and MMSET gene in MM cell line NCI-H929.The

breakpoints were located within the Cμregion of IgH gene on chromosome14and intron3of MMSET gene on chro-

mosome4.IgH-MMSET hybrid transcripts were detected in3of25MM patients through nested PCR assay.The am-

plified fragments of the3patients were237base pairs(bp),239bp and239bp in length,respectively.The break-

points on chromosome4were identical to that of NCI-H929cell.Co nclusions　The formation of IgH-MMSET fusion

gene is resulted from t(4;14)translocation in MM.The incidence rate is12.0%.The presence of IgH-MMSET fu-

sion gene may predict poor prognos is.

【Key words】　Multiple myeloma;　Gene fusion,IgH-MMSE T;　Translocation(Genetics)

多发性骨髓瘤(MM)是浆细胞恶性增殖性疾病。通过细胞遗传学及分子生物学技术检测发现MM的核型变化较其它类型的血液系统肿瘤更为复杂。其中涉及人免疫球蛋白重链(IgH)基因定位的14号染色体(Chr14)的结构异常发生率为20%～60%。大多数是由于伙伴染色体与Chr14交互易位造成的,

基金项目:教育部高校骨干教师基金;上海市卫生局“百人计划”课题(98BR032);全军“九五”课题(98M082)资助项目

作者单位:200003　上海,第二军医大学长征医院血液科从而形成MM特殊的标志染色体14q+和14号染色体缺失,即del(14)。交互易位后形成IgH及其伙伴染色体的融合基因,融合基因的检测对于监测微小残留病(MRD)、评价临床疗效及预后等方面都具有重要意义。文献中报道t(4;14)可见于10%～20%的MM[1-3],基因易位后造成IgH基因与位于4号染色体(Chr4)上的MMSE T(Multiple myeloma SE T do-main)基因相连接出现IgH-MMSET杂合转录。我们采用RT-PCR及巢式PCR方法在25例MM患者中