TCF3-PBX1融合基因阳性成人急性淋巴细胞白血病的临床和实验研究

目的 探讨TCF3-PBX1融合基因阳性的成人急性淋巴细胞白血病(ALL)的形态学、免疫学、细胞遗传学和临床特点.方法采用R显带技术进行常规核型(CC)分析,间期荧光原位杂交(FISH)技术和RT-PCR技术检测TCF3-PBX1融合基因,流式细胞术(FCM)检测细胞免疫表型;分析19例TCF3-PBX1融合基因阳性成人ALL的临床和实验室特征并进行长期随访.结果本组19例TCF3-PBX1融合基因阳件ALL占同期成人ALL的3.13%;其中L_2 12例,L_2 7例.细胞遗传学检测7例为t(1;19)平衡易位,10例为der(19)t(1;19)不平衡易位,2例为正常核型.9例经RT-PCR检测的病例均有TCF3-PBX1融合基因转录本,17例经间期FISH检测TCF3-PBX1融合基因均为阳性.18例行FCM检测的患者中16例为B淋系抗原表达,2例为T淋系抗原表达.17例患者有不同程度的肝、脾、淋巴结等髓外浸润.本组患者经1个疗程诱导化疗后17例获得完全缓解(CR),CR率为94.7%,中位无复发生存时间为3.2个月,中位总生存期为7.2个月.结论 TCF3-PBX1融合基因阳件成人ALL有着独特的临床和实验室特点;治疗缓解率高,但短期内易复发,总生存期短,应该采取更积极的治疗以改善预后;间期双色FISH联合CC及RT-PCR可以提高TCF3-PBX1融合基因的检出率.

A clinical and laboratory study of TCF3-PBX1 positive adult acute lymphoblastic leukemia

Objective To explore the morphology,immunophenotype,cytogenetics and clinical features of TCF3-PBX1 fusion gene positive adult acute lymphoblastic leukemia(ALL).Methods R banding was used to analyze conventional cytogenetics(CC),interphase fluorescence in situ hybridization(iFISH)and RT-PCR to detect the TCF3-PBX1 fusion gene,and flow cytometry to immunophenotype.The clinical and laboratory features and long-term follow-up of the patients were analyzed.Results The incidence of 19 TCF3-PBX1-positive adult ALL was 3.13% of total ALL patients.Of them,12 and 7 cases were diagnosed as L_1 and L_2 morphology respectively;7 cases with balanced translocation of chromosome 1 and 19;10 with der(19)t(1:19)formed from unbalanced translocation and 2 with normal karyotypes.TCF3-PBX1 fusion gene was detected by RT-PCR in 9 cases,and by iFISH in 17.16 cases were B-phenotype and the other 2 T-phenotype;17 cases had lymph node,spleen or liver infiltration.Of 18 patients received chemotherapy,17(94.7%)achieved complete remission(CR);the median relapse-free survival(RFS)and median overall survival was 3.2 months and 7.2 months,respectively.Conclusions TCF3-PBX1-positive adult ALL had unique clinical and pathological features with high remission rate,high relapse rate and short survival time and should be considered to receive intensified treatment strategies.iFISH combined with CC and RT-PCR can increase the detection rate of t(1;19)/TCF3-PBX1 fusion gene.